drinking water 2015 · drinking water 2015 4 chapter 1: summary chapter 1: provides a summary of...

Drinking water2015Public water supplies in the Northern region of EnglandJuly 2016A report by the Chief Inspector of Drinking Water

Northe rn reg ion

1

Drinking water 2015

Northern region of England

Dr ink ing wate r 2015

2

Publ ished by

Dr ink ing W ater Inspectorate

Area 7e

9 Mi l lbank

c/o Nobel House

17 Smith Square

London

SW 1P 3JR

Tel: 0300 068 6400

Website: http: / /www.dwi.defra.gov.uk

© Crown Copyr ight 2016

ISBN: 978-1-905852-98-7

Copyr ight in the typographical arrangement and des ign rests wi th the Crown.

This publ icat ion (exc luding the logo) may be reproduced f ree of charge in any

format or medium provided that i t is reproduced accurate ly and not us ed in a

misleading context . The mater ia l must be acknowledged as Crown copyr ight wi th

the t i t le and source of the publ icat ion spec if ied.

Northe rn reg ion

3

Contents

Chapter 1: Summary 4

Chapter 2: Water supply arrangements 11

Chapter 3: Drinking water qual ity test ing 15

Chapter 4: Drinking water qual ity results 18

4.1 Microbiological qual ity 18

4.2 Chemical qual ity 28

Chapter 5: Drinking water qual ity events 52

Chapter 6: Technical audit act iv ity 61

Annex 1: Further sources of information 68

Annex 2: Guidance and research publ ished by DWI 69

Annex 3: Drinking water qual ity events in the region 71

Annex 4: Planned drinking water quality improvements 107

Annex 5: Compet it ion in the water industry 110

Annex 6: Water company indices 112

Annex 7: Glossary and descript ion of standards 115

Drink ing water 2015 is the annual repor t o f the Dr ink ing Water Inspecto rate and

compr ises reports cover ing publ ic and pr ivate water suppl ies .

Publ ic suppl ies – Th is par t descr ibes dr ink ing water qual i ty in the Northern reg ion. The

Inspectorate a lso publ ishes a ser ies of companion reports fo r o ther reg ions of England

(Centra l and Easte rn, London and South East and Western reg ions) and a separate

report fo r Wales.

Pr ivate suppl ies – A summary of in format ion on pr ivate water suppl ies i s reported fo r

England and Wales.

Al l par ts are avai lab le on the Inspectorate ’s websi t e www.dwi .defra.gov.uk


4

Chapter 1: Summary

Chapter 1:

Provides a summary of the report for the Northern region.

Puts drinking water quality in the region into conte xt nat ional ly.

Drinking Water 2015 is the annual publ icat ion of the Chief Inspector of

Drinking Water for England and Wales. I t is the 26 t h report of the work of

the Inspectorate and presents information about dr inking water quality for

the calendar year of 2015. I t is published as a series of seven reports, f ive

of which cover publ ic water suppl ies and two descr ibe private water

suppl ies. This report is about publ ic supplies in the Northern region of

England.

Set out in this report are the key facts about the qual ity of the publ ic water

suppl ies in the Northern region, which is served by six water companies

del ivering suppl ies to 14 mill ion consumers. The area served by each

water company is shown in Figure 1 and the organisation and nature of

water suppl ies in the Northern region is described in more detai l in

Chapter 2. There were no changes in the water supply arrangements in the

region in 2015 compared to 2014 and l it t le change in the number of private

water suppl ies in the region not if ied by local aut hor it ies to the Inspectorate

with the total in 2015 marginal ly decreasing f rom 11,344 reported in 2014.

Detailed information about the regulat ion and qual ity of private suppl ies

can be found in the separate report ent it led Drinking Water 2015 – Pr ivate

Water Suppl ies in England.

The quality of publ ic water suppl ies in England/Wales in 2015 was very

high with only 0.04% of tests fail ing to meet the European Union (EU) and

national standards. This compares favourably to the 1.6% of failures

recorded in 1991, the f irst year af ter privat isat ion of the water industry,

when regulat ion of drinking water qual ity was f irst introduced. The

situat ion in relat ion to the qual ity of private water suppl ies in

England/Wales remains less satisfactory with 4.5% of tests fail ing to meet

the EU and nat ional standards in 2015. However, this f igure compares

favourably to the 7.5% of tests that failed in 2010, the year when new

regulat ions implementing the EU Drinking Water Direct ive for private

suppl ies were introduced.

Northe rn reg ion

5

Figure 1: Water supply arrangements

The results of test ing of public suppl ies in 2015 demonstrated that overal l

the qual ity of drinking water in the Northern region was good. The f igure

for compliance with drinking water standards was 99.96%, up on the

regional f igure in 2014, and the same as the industry average. The

Inspectorate uses a range of indices to assess the water qual ity

performance of the companies providing public suppl ies. These indices 1

look in turn at water treatment (process control and disinfe ct ion indices),

1 Calculat ion method for indices is publ ished at

ht tp:/ /dwi .defra.gov.uk/about/annual -report /ca lculat ing - indices.pdf


6

service reservoir integrity and network maintenance. Individual water

company f igures are set out in Annex 6 . In 2015 the changes in the

Northern region were improvement in the f igures for distr ibut ion

maintenance and consumer protect ion ; the f igures for process control and

disinfect ion were lower than last year ; and the f igure for reservoir integrity

was unchanged. Nevertheless al l except the disinfect ion indices were at or

around the industry averages.

Figure 2 shows how the change in the dis infect ion index for the region in

2015 compared to the industry average. Al l companies showed an

improvement in performance or remained the same with the except ion of

Northumbrian Water due to an E.coli detect ion and an increase in turbidity

failures at treatment works. As a result , the region showed a decline in the

index f rom 99.97% in 2014 to 99.92% in 2015. Northumbrian Water moved

into the lowest posit ion in the region and below the industry average.

United Ut i l i t ies, whi le remaining the same for 2015, nonetheless had a

notable deteriorat ion in col iform failures (see Chapter 4.1 – Microbiological

quality), which was only balanced by an improvement in turbidity failures.

Figure 2: Company performance for the disinfection index

Across the Northern region, in 2015, there were signif icant ly more events

affect ing water quali ty overal l (111 compared to 77 in 2014), a continuing

trend from 2013. A number of notable recurring themes in the region in

2015 were: improper ly dis infected water due to inappropr iate process

control issues; discolourat ion/loss of suppl ies due to inadequate

supervis ion of contractors; and inadequate r isk assessments prior to

routine and planned work. Annex 3 provides further detai ls and while these

were addressed via the events assessment process, companies should

Northe rn reg ion

7

continue to be part icular ly vigilant around these themes as they wi l l be

taken into account during the Inspectorate’s r isk -based programme of

technical audit .

In 2015 in the Northern region there were three ser ious events (2 UUT, 1

NNE). United Ut i l i t ies required a boi l water notice init ia l ly to 700,000

consumers fol lowing the detect ion of Cryptosporidium at its Franklaw

works serving areas around Blackpool, Preston and Fleetwood. The

complexity of the system and the inabi l i ty to easi ly support large areas

uniquely supplied by this works exacerbated expedit ious recovery. The

second serious event at United Uti l i t ies was at Sweetloves works which

required a boi l not ice and alternative suppl ies to approximately 79,300

consumers for three days due to loss of pH process control, cr it ical for

effect ive dis infect ion. This event i l lustrates the failure of a known r isk to

have adequate systems in place as mit igat ion. In October 2015

Northumbrian Water required 750 consumers not to dri nk water due to

back-siphonage of industr ial chemicals , when the company were working

on an industr ial estate , due to an inadequate r isk assessment and

backf low prevent ion to protect the publ ic supply. Further detai ls of these

and all events can be found in Annex 3 . Addit ional ly, in December 2015 ,

storm Desmond had a signif icant impact for United Ut i l i t ies. There were a

number of events affect ing water suppl ies, including works shutdown at

Bridgend, Eden Br idge and Buttermere due to severe f looding followin g

heavy rainfal l af fect ing the Cumbria and Northern Lancashire areas.

Suppl ies were supported where possible through rezoning, use of tankers

to support local reservoirs and provision of bott led water emphasising

good contingency planning by United Uti l i t i es to minimise the dif f icult ies

exper ienced by consumers in the area at an already challenging period.

In 2015, two events occurred at large treatment works (Frankley works

(Severn Trent Water) and Franklaw works (United Ut il i t ies)) which

identif ied issues for considerat ion by all companies. The failure of these

two treatment works highl ighted the need for longer strategic planning to

avoid failure to supply wholesome water to consumers at al l t imes where

there is no obvious opportunity to recover. Plans s hould include

interconnection between works and systems, process redundancy,

operat ion within design l imits, technology and competent staff al l brought

together through r isk assessment and mit igat ion. This year, companies

submitted their r isk assessments to the Inspectorate and it is clear that

long-term asset planning for water quality wi l l need to be a priority.

The Inspectorate, as part of its r isk -based strategy, ident if ied Severn Trent

Water and United Ut i l i t ies as companies where the r isk of regulator y

failure was considered greatest and where a r isk reduction program me to

support improvement through programmes of work was merited. Severn

Trent Water, who were the f irst company to engage with the transformation


8

programme following a number of chal lenging years reported in the Chief

Inspector ’s reports of 2014 and 2013, agreed an extensive forward plan for

improvement cover ing works and service reservoirs. The Inspectorate is

pleased to report that whi le the process is st i l l ongoing, the posit ive

response by the company has shown benef its in the reduction of r isk. The

transformation programme for United Uti l i t ies started at the end of the

year. The programme encompasses a much wider range of r isks , including

the need to refocus company staf f on drinking water qual ity and

reposit ioning the organisation as a service company to meet customer

needs and expectat ions. The Inspectorate reminds companies that

overemphasis on a selected number of end point compliance parameters

can result in failure to identify key r isks throughout the supply of water ,

which consequent ly results in fai lure to produce a clean wholesome

supply.

Local authorit ies across England and Wales provided case studies on the

remediat ion of fail ing private water suppl ies. One example relat ing to the

Northern region can be found in Drinking water 2015 – Pr ivate water

suppl ies in England – Chapter 3: Improving private water suppl ies.

More information and industry-wide learning points about these and other

signif icant events can be found in Chapter 5: Drinking water qual ity events

and a summary of al l signif icant events in the region can be found in

Annex 3 of the report.

Table 3: Water quality events in 2015

Nature of event

Risk assessment category (DWI)

Minor* Signif icant Serious**

2014 2015 2014 2015 2014 2015

Centra l and Eastern 119 129 59 48 5 4

London and South East 90 97 53 62 6 2

Nor thern 28 44 48 64 1 3

Western 32 38 53 33 - 1

Wales 13 16 10 18 - -

Industry 281 322 218 223 12 10 Four events af fected two or more reg ions in 2015 an d f ive in 2014. *Minor category numbers inc lude a l l not s ign i f icant and minor events . **Ser ious category numbers inc lude a l l ser ious and major events .

During 2015, the Inspectorate carr ied out 88 audits of assets, sampling

arrangements and consumer complaints in England and Wales, 17 of which

were in the Northern region. In addit ion, the Inspectorate received reports

submitted by the industry which identif ied r isks f rom source to tap for all

supply systems. These detailed reports are currently under revie w and the

outcomes wil l be reported in the Inspectorate’s new quarterly report.

When consumers are dissat isf ied with the quality of their dr inking water

they may contact their water company. Records of the numbers of contacts

Northe rn reg ion

9

received by water companies are sent to the Inspectorate each year. In the

Northern region, the total number of consumer contacts to water

companies about the quality of drinking water was 2.0 contacts per 1,000

populat ion, higher than the industry average of 1.6 contacts per 1,000

populat ion. I f the water company fails to address the consumer’s water

quality issue, the consumer can seek assistance from the Inspectorate. In

2015, the Inspectorate investigated 47 consumer complaints of which

seven (4 UUT, 3 YKS) were in the Northern region.

Also, during 2015, the Inspectorate handled 297 requests for advice about

private suppl ies f rom local authorit ies across England and Wales and 94 of

these enquir ies were from the Northern region. Audit f indings and

consumer complaint case examples can be found in Chapter 6 , and detai ls

of the work of the Inspectorate in relat ion to private suppl ies can be found

in the companion report entit led Drinking water 2015 – Pr ivate water

suppl ies in England.

Turning to planned improvements in dr inking water qual ity in the region,

during 2015, the Inspectorate conf irmed the need for improvements at a

number of assets. United Uti l i t ies were served with 12 Legal Instruments.

Four were to address dis infect ion issues (Sweet loves, Clough Bottom,

Loveclough and Laneshaw); two for taste and odour issues (Clough Bottom

and Denton); and four at service reservoirs for ingress (Gorsehi l l No.2,

Flaybrick, Brown Edge and Prenton Lower). Yorkshire Water was issued a

Notice for Cryptosporidium control at Rivel in works; Hart lepool Water for

turbidity at Amerston Hal l; and Northumbrian Water was issued a

Regulat ion 28 Notice for contamination within the Bi l l ingham and

Middlesborough zone.

Companies in the region are committed to complet ing the planned work

summarised in Annex 4 dur ing the AMP6 period (2015–2020) and all

schemes in the region are proceeding in l ine with agreed t imescales.

By way of comparison, in 2015, local authorit ies in the Northern region put

in place 190 improvement Notices in relat ion to fai l ing private water

suppl ies.

The requirement for companies to complete a r isk assessment for every

treatment works and supply system was init iated as part of the 2007

amendments to the Regulat ions. In October 2015, the Inspectorate

completed its project for a database, which sets a commonly agreed

framework for summary r isk assessment reports demonstrat ing company

compliance with the Regulat ions. The database col lects r isk information

associated with catchments, treatment works, service reservoirs and

zones, and lets the Inspectorate scrut inise those r isks and related

mit igat ions . The Inspectorate’s assessment of the r isk information and any

result ing enforcement act ion is also vis ible . This key change embraces the


10

principles of r isk assessment and better regulat ion. The databa se makes

information avai lable in expectat ion of the transposit ion of Annex II of the

Drinking Water Direct ive late in 2017. Annex II permits the variat ion of

sampling f requencies based on the outcome of the r isk assessment. Work

is currently ongoing to develop the outcomes of the assessments and this

wi l l be taken into account in the r isk -based response of the Inspectorate

going forward.

The Inspectorate provided the water industry with technical advice on six

topics to enable water suppl iers to comply wit h the drinking water

regulat ions. In addit ion, eight research projects were published by the

Inspectorate to develop underpinning knowledge for regulatory r isk

assessments. Annex 2 l ists al l of the advice and research published by the

Inspectorate in 2015.

Northe rn reg ion

11

Chapter 2: Water supply arrangements

Chapter 2:

Identif ies the water supply companies in the region .

I l lustrates the water source and supply arrangements in the region .

Provides summary f igures describing the water supply assets and

stakeholders.

Figure 4: Map il lustrating sources of drinking water by zone across

the region


12

Six water companies supply drinking water in the Northern region: Dee

Val ley Water (DVW); Hart lepool Water (HPL); Northumbrian Water (NNE);

United Ut i l i t ies (UUT); and Yorkshire Water (YKS) and two inset

appointments; Peel Water Networks (PWN) supplying Media City in Salford

Quays, Greater Manchester and Hart lepool Water serving part of the

Wynyard Business Park and a development near Wolviston.

Much of the water suppl ied in the reg ion originates f rom surface water

(83%), abstracted f rom rivers such as the Dee, Derwent, Eden, Lune,

Ouse, Tees, Tyne and Wyre. The main reservoir sources supplying the

region are the Derwent reservoir in the Pennines and other large

reservoirs l ike Kielder in Northumberland, Haweswater and Thir lmere in

Cumbria and Vyrnwy in Wales. Natural lakes are an important regional

water resource, with abstract ions f rom Crummock Water, Ennerdale,

Windermere and Ullswater.

Groundwater provides a valuable resource in t he region (11%). Most

boreholes draw water f rom the sandstone aquifers, between Doncaster and

Selby, in the Eden Val ley, f rom Cheshire and West Lancashire aquifers

and from the Fylde aquifer. Hart lepool Water rel ies exclusively on

groundwater f rom the l imestone aquifer in southeast Durham and this

source of water also suppl ies the Sunderland area (suppl ied by

Northumbrian Water). There is another important chalk aquifer in the

Yorkshire Wolds. The remainder (6%) of water suppl ies in the region can

be drawn from either surface or groundwater sources.

Private water suppl ies in the region are widely distr ibuted across the area.

These private suppl ies are more rel iant on groundwater (55%) than the

public suppl ies in the area (11%). For more information about pri vate

water suppl ies please refer to Drinking Water 2015 – Private water

suppl ies in England/Wales.

Figure 5 i l lustrates the location of private and public supply groundwater

abstract ion points in relat ion to the groundwater aquifers in the region.

Northe rn reg ion

13

Figure 5: Location of private and public supply groundwater

abstraction points

Summary facts about the drinking water supply infrastructure of the region

are given in Table 6 with outl ine geographical and demographic

information.


14

Table 6: Key facts about public and private water supply arrangements

in the Northern region

Public supplies Private supplies

Population supplied Water supplied (l/day) Abstraction points Treatment works Service reservoirs Water supply zones Length of mains pipe (km)

14,689,343 3,724 million 370

185 1,018 368 92,015

Population supplied Water supplied (l/day) Approximate number of private water supplies* Total number of local authorities

Number of local authorities with private supplies

204,775 69 million

11,335

70

62

Water composition

Surface sources Groundwater sources Mixed sources

81.5% 11% 7.5%

Water composition

Surface influenced supplies Groundwater sources Mains water

Unknown

35% 55%

2%

8%

Area of supply Cheshire, Cleveland, County Durham, Cumbria, Derbyshire (part), Lancashire, Merseyside, Greater Manchester, North Lincolnshire, Northumberland, Tyne and Wear and Yorkshire.

Northe rn reg ion

15

Chapter 3: Drinking water quality testing

Chapter 3:

Explains the basis of the drinking water test ing programme.

Records the number of tests carr ied out by water companies.

Identif ies any def ic iencies in water test ing and how these have been

remedied.

Throughout 2015, water companies sampled drinking water across the

region to ver ify compliance with the dr inking water regulat ions . Near ly half

the tests were carr ied out on samples drawn from consumers’ taps

selected at random. For monitor ing purposes, company water supply areas

are divided into zones. Sampling in zones at consumers’ taps is r isk-based

with the number of tests being higher in zones with a large populat ion

(maximum 100,000). Other sample locat ions are water treatment works and

treated water (service) reservoirs. Col lect ively, the six water companies

carr ied out a total of 968,751 tests dur ing 2015 and only 259 of these tests

failed to meet one or more of the standards set down in the Regulat ions or

exceeded a screening value.

Table 7: Number of tests carried out by companies in the region

Company

Place of sampling Number of tests

per company

Target number of

tests

Water treatment

works

Service reservoirs

Consumers’ taps

(zones)

Dee Val ley Water

5,506 (2)

312 (1)

4,342 (4)

10,160 10,161

Har t lepool Water

748 (2)

1,560 (6)

2,272 (2)

4,580 4,580

Nor thumbr ian Water

41,899 (35)

63,360 (205)

77,035 (65)

182,294 182,442

Peel Water Networks

0 (0)

0 (0)

365 (1)

365 365

Uni ted Ut i l i t ies

107,242 (77)

110,026 (355)

195,977 (225)

413,245 413,426

Yorkshire Water

100,661 (59)

104,622 (344)

152,824 (71)

358,107 358,114

Region overall

256,056 (175)

279,880 (911)

432,815 (368)

968,751 969,088

Note: Numbers in b rackets re f lec t the number o f works , reservo i rs or zones operated by that company in the reg ion in 2015. Some companies a re perm i t ted to ca r ry out some tes ts on samples taken f rom supply po in ts ra the r than f rom consumers ’ taps .

The Regulat ions set out the parameters to be tested for by water

companies. Most of the test ing is for parameters with a European or

national standard (Schedule 1 parameters) , however, water companies are

also required by the Regulat ions to test for other indicator parameters


16

(Schedule 2 parameters). The Regulat ions also lay down how many of

these tests must be done each year (Schedule 3) and the Inspectorate

checks that the water companies are meeting these sample f requencies.

Across the region in 2015 there was a shortfall in sample numbers .

United Ut i l i t ies (181), Northumbrian Water (148), and Yorkshire Water (7),

Scott ish and Southern Energy Water (8) and Thames Water (148) were

unable to provide test results, (numbers in brackets), for analysis. Th ese

were due to a combination of reasons including fail ing to revise the sample

programme when a works or reservoir is out of supply (NNE 148, UUY 36),

failure to schedule or reschedule samples (UUT 129), errors or q uality

failures during analysis (UUT 8, YKS 7) and dif f icult ies with bulk suppl ies

(UUT 8).

Companies are reminded to meet the dut ies placed upon them by

Regulat ions and that senior managers should be taking steps to satisfy

themselves, through regular internal reports, that the sampling program me

is being act ively managed and the systems are providing accurate data .

Without all data there cannot be a complete assessment and , as a result ,

loss of conf idence in the company performance. Th is necessitated the

serving of Final Enforcement Orders for two companies in the London and

South East region requir ing the appropr iate submission of all data in the

forthcoming year. Further detai ls can be seen in Drinking water 2015 –

Publ ic water suppl ies in the London and South East region .

The Regulat ions also require that the water samples are representat ive of

water being suppl ied to consumers and there are requirements to ensure

the qual ity of the analysis of samples in the laboratory. In 2015, there

were no such events in the region where sampling or analys is was not to

the required standard. However, there was one compliance fai lure for

f luoride (HPL), further detai ls can be found in Chapter 4.

In October 2015, the European Commission adopted and publ ished

replacement Annexes II and II I to the Drinking Wate r Direct ive. These

changes permit the option of moving away from statutory minimum

frequencies of sampling for a set l ist of parameters, introducing a r isk -

based approach of determining which parameters to monitor and at what

f requency. The change in f requency, removal or addit ion of parameters is

intended to be based upon histor ical monitoring data f rom f inal and raw

water as wel l as r isk assessments and wil l br ing the advantage of

companies not having to unnecessar i ly carry out analysis and to

concentrate on controls that protect publ ic health. The development of the

Inspectorate ’s own r isk-based methodology wil l help determine if the

company applicat ion of these principles is being adopted. I t wil l further

seek to ident ify an understanding of company r isk , based upon a changing

Northe rn reg ion

17

dataset. The Inspectorate wil l communicate this changing strategy in

future Chief Inspector reports.

As an addit ional change to the Drinking Water Direct ive, Annex II I

introduces new accepted standards for methods of analysis for

microbiological parameters and changes def ined performance

character ist ics f rom ‘Trueness’, ‘Precision’ and ‘ l imit of detect ion’ to

‘Uncertainty of Measurement’. The DWI has a programme in place for the

transposit ion of these requirements scheduled for Octo ber 2017.


18

Chapter 4: Drinking water quality results

Chapter 4:

Provides details of tests fail ing to meet microbiological and chemical

standards.

Comments on the remedial act ion taken by the water company or the

Inspectorate.

The key water quality result s for the Northern region are presented in two

tables, one showing the results for microbiological parameters (Table 8),

the other deal ing with chemical and physical parameters (Table 12). The

microbiological quali ty of water is discussed f irst. Companies report al l the

results of the tests on a monthly basis to the Inspectorate. A summary of

the results of test ing for all parameters and tables that describe the

drinking water qual ity performance indices of each company can be found

on the DWI website (www.dwi.defra.gov.uk).

Microbiological quality

To protect public health, microbiological standards have to be met at each

individual treatment works and service reservoir. The signif icance of the

individual test results for each microbiological parameter at e ach locat ion

var ies and a single posit ive result cannot be interpreted without other

information. Al l companies are expected to follow best pract ice as set out

in The Microbiology of Drinking Water publ ished by the Standing

Committee of Analysts (SCA) which can be found by vis it ing the website at

https:/ /www.gov.uk/government/publicat ions/standing -committee-of-

analysts-sca-blue-books.

Northe rn reg ion

19

Table 8: Microbiological tests

The number of tests performed and the number of tests not meeting

the standard

Parameter Current

standard

Total number of tests

Number of tests not meeting

the standard

Addit ional information

Water leaving water t reatment works

E.col i 0/100ml 36,117 1 NNE (1)

Col i form bacter ia 0/100ml 36,117 13 NNE (2) , UUT (9), YKS (2)

Clostr id ium per fr ingens

0/100ml 14,529 6 UUT (5), YKS (1)

Turbid i ty1 1NTU 36,160 13

DVW (1), NNE (6) , UUT (1), YKS (5)

Water leaving service reservoirs

E.col i 0/100ml 46,698 0

Col i form bacter ia

0/100ml in 95% of tes ts

at each reservoir

46,698 22

NNE (4) , UUT (9), YKS (9) Al l 911 reservoirs in the region met the 95% compl iance ru le

Water sampled at consumers’ taps

E.col i 0/100ml 37,132 2 UUT (1), YKS (1)

Enterococc i 0/100ml 2,939 4 NNE (3) , UUT (1) 1Turb id i ty is a cr i t ica l contro l parameter for wate r t reatment and d is in fect ion.

E.coli at works and service reservoirs

In 2015, a total of 82,815 tests at works and reservoirs were carr ied out by

al l the companies across the region. E.coli was detected in only one

sample at a treatment works. No E.coli was detected at service reservoirs .

Despite only one sample detect ing E.col i , this compares unfavourably with

the excel lent result in 2014 when no detect ions were reported in either

works or service reservoirs.

On detect ing E.col i , companies are required to act prompt ly to protect

public health. Their immediate response when f inding E.col i at a works is

to sample again, and more widely, to conf irm that water being received by

consumers is safe. In 2015, al l these addit ional tests gave satisfactory

results and there were no subsequent E.col i failures.

At Lart ington works (near Dar l ington) in August , Northumbrian Water failed

to identify the cause of an E.coli detect ion. However, this works has

suffered with poor process control in June and September res ult ing in

elevated and then suboptimal dis infect ion. Fai lure of proper and adequate


20

control wi l l inevitably reduce the abil i ty of a works to operate effect ively

and should be taken into account during a company’s r isk assessment

methodology. Further detai ls can be seen in Annex 3 .

Table 9: Detection of E.coli and Enterococci at treatment works,

service reservoirs and consumers’ taps

Company

E.coli in water leaving

treatment works

E.coli in water

leaving service

reservoirs

E.coli at consumers’

taps

Enterococci at

consumers’ taps

Dee Val ley Water

0 – 783 0 – 52 0 – 293 0 – 38

Har t lepool Water

0 – 116 0 – 312 0 – 228 0 – 12


1 – 5 ,932 0 – 10,560 0 – 6 ,488 3 – 538

Peel Water Networks

0 – 0 0 – 0 0 – 24 0 – 14

Uni ted Ut i l i t ies Water

0 – 15,224 0 – 18,337 1 – 18,340 1 – 1 ,768

Yorkshire Water

0 – 14,062 0 – 17,437 1 – 11,759 0 – 569

Region overal l 1 – 36,117 0 – 46,698 2 – 37,132 4 – 2 ,939

Note: Resu l ts are shown as the number o f pos i t i ve tes ts – the to ta l number o f tes ts .

Coliform bacteria at works

Testing for coliform bacteria gives reassurance that water entering supply

was treated adequately to remove bacter ial and viral pathogens. Repeated

occurrences of col iform bacteria in samples f rom the same works in one

year are thus of concern and require act ion to be taken. In 2015, this

situat ion did not occur at any of the 185 works in the region.

In February, Northumbrian Water originally fai led to identify the cause of a

col iform failure at Fontburn works near Rothbury. Ongoing investigations

eventual ly found ingress into the contact tank, which was then repaired.

Coliform failures were detected in samples f rom nine works operated by

United Ut i l i t ies: Ashworth Moor and Bickerstaffe (January), Hurleston and

Cornhow (March), Sutton Hal l No 1 and Buckton Cast le (Apri l) , Lancaster

(June), Tyther ington (July) and Prescot New (November). While

investigations were conducted for all fai lures , the company were unable to

identify the root cause at seven sites. At four of these sites (Sutton Hal l

No 1, Hur leston, Prescot New and Cornhow) the failures were attr ibuted to

problems with the sampling facil i t ies that have since been remedied and

al l subsequent results f rom this site have proved sat isfactory. However, at

Cornhow works near Cockermouth, there have been previous col iform

Northe rn reg ion

21

failures (2009 and 2014) and turbidity (2015) . The Inspectorate issued a

Notice requir ing the contact tank and clear water tank to be inspected and

the integrity of their construct ional concrete to be tested (see Annex 4).

The programme of work was completed in early 2016 with the company

having addressed def iciencies relat ing to the f inal water sampling

arrangements and f inal water tank roof membranes were replaced. There

have been no further issues to date.

At Buckton Castle works, operated by Un ited Ut i l i t ies near Mossley,

ingress into the contact tank was rect if ied. At Tyther ington works

(Macclesf ield) , whi le no cause was found, the Inspectorate considered

errat ic turbidity measurements in associat ion with an inappropriate site -

specif ic dis infect ion pol icy required act ion. The company quickly improved

the policy suf f icient to mit igate concerns about turbidity and dis infect ion.

A protracted investigation at Lancaster works identif ied a number of

operat ional def iciencies, but of most concern was a fault with the primary

dis infect ion process of UV irradiance. There was a fault with the

transmissivity monitor, which was not repaired for over a month whi le

spare parts were del ivered. To mit igate the r isk addit ional UV lamps were

used in the dis infect ion process, but their use was not capable of

val idat ion. The Inspectorate was cr it ical of this and companies are

reminded of the need to meet the requirements of Regulat ion 26 at al l

t imes and also the need to be able to show full val idat ion for this type o f

equipment.

There were col iform bacteria failures at two works operated by Yorkshire

Water (Lof tsome Bridge, near Hemingbrough and Cat ter ick No 2 near

Brompton-on-Swale). At Lof tsome Bridge works the company reported that

just prior to sampling the works was out of supply due to a power outage.

Their invest igation found no cause, which was also the outcome of the

investigation at Catterick No 2 works, but here the company upgraded the

sampling arrangements.

Companies are reminded that they should be regula r ly inspecting their

assets to ident ify developing issues ear ly, escalat ing invest igation,

inspect ion and r isk information so that senior management is clear about

the need to improve planned preventat ive maintenance and pr iorit isat ion of

the company response.

The Inspectorate has noted that col iform bacteria were found in 13

samples f rom treatment works in the Northern region during the year. This

information wi l l be taken into account dur ing the Inspectorate’s r isk -based

programme of technical audit .


22

Clostridium perfringens

This organism is a spore-forming bacterium that is exceptional ly resistant

to unfavourable condit ions in the water environment, such as extremes of

temperature and pH, and disinfect ion processes such as chlor inat ion and

ultraviolet l ight. I t is a normal component of the intest inal f lora of up to

35% of humans and other warm-blooded animals. These characterist ics

make it a useful indicator of either intermittent or historical faecal

contamination of a groundwater source or the performan ce of a surface

water f i l t rat ion plant. The detect ion of any Clostr idium perfr ingens should

tr igger an invest igation by the water company.

In 2015, out of 14,529 samples taken in the region, s ix did not meet the

specif ied value (5 UUT, 1 YKS). All f ive fai lures reported by United Ut i l i t ies

were col lected f rom consumers’ taps and al l follow-up samples were

satisfactory. However, Clostr idium perfr ingens is an indicator organism

primari ly used to determine the performance of f i l t rat ion at surface water

works. Companies should be test ing for this parameter at works and other

suitable supply points (not at consumers ’ taps) when daily sampling at

large works is not suff icient to meet the f requency of test ing which der ives

f rom the EU Drinking Water Direct ive. Clostr idium perfr ingens is a

component of historic mains deposits in distr ibut ion networks fed by

surface water works and occasional fai lures at consumers’ taps are not

uncommon in these circumstances. The Inspectorate welcomes how most

companies have taken steps to stop test ing at consumers’ taps for this

parameter thereby avoiding inconveniencing consumers with inconclusive

plumbing hygiene investigations. I t is disappoint ing to n ote that United

Uti l i t ies cont inues to adopt this poor pract ice .

While all fol low-up samples for United Ut il i t ies were sat isfactory, the

sample f rom one water supply zone (Liverpool Ctm 40 inch) was noted that

the supplying treatment works (Oswestry works) was without dis infect ion

for approximately four hours at the t ime of collect ion . The company had

failed to report this improperly disinfected water as an event and were

required to do so, the details of which are recorded in Annex 3 .

The single detect ion of Clostr idium perfr ingens for Yorkshire Water

(Rivel in works near Sheff ield) in Apr il was reported as an event (see

Annex 3). The investigation by the company was inconclusive, but there

was a potent ial associat ion with points of ingress in an intermediate tank,

together with poor f low character ist ics. The tank was remediated and f low

character ist ics improved with better control of the water f low (see Annex

3). There have been no further detect ions.

Northe rn reg ion

23

Turbidity at works

Turbidity is a measure of how much l ight can pass through water and

indicates the ‘cloudiness’ of water. Turbidity m ay be caused by either

inorganic or organic part ic les suspended in the water. At a treatment

works turbidity is an important cr it ical control in relat ion to determining

whether raw water has been adequately prepared for disinfect ion. Turbidity

standards are set at two points in the water supply chain, at treatment

works and at consumers’ taps. The following discussion focuses on the

results of samples taken at treatment works where the standard is 1 NTU.

The results of turbidity test ing at consumer taps can be found in the

Maintaining water qual ity in distr ibut ion sect ion.

Groundwater works

Where turbidity arises in groundwater it is usual ly as a consequence of

disturbance of inert clay or chalk part ic les , but it can also arise f rom the

oxidation and precipitat ion of certain inorganic substances l ike iron and

manganese when air is introduced into the water by pumping. I f the

groundwater is under the inf luence of surface water then the cause of

turbidity may be part ic les with adherent biological matter, which m ay

contain pathogens.

Irrespective of origin, turbidity can interfere with the eff iciency of

dis infect ion. Turbidity is therefore a crit ical control measure that should be

val idated at a groundwater works by continuous on - l ine monitoring of raw

water with alarms set to ensure that act ion is taken to guarantee that

turbidity is <1NTU at al l t imes. Where a r isk f rom Cryptosporidium has

been identif ied in relat ion to a groundwater source and its catchment, then

companies should be carrying out monitoring of th e raw water and this

should be taken into account when determining the nature of the r isk and

the suff iciency of the control measures.

Table 10 i l lustrates the potential groundwater Cryptosporidium r isk in the

region and compares it to the actual Cryptosporidium r isk in 2015. Out of a

total of 148 groundwater raw water abstract ion points where data were

submitted, 39 were subjected to r isk -based monitor ing for Cryptospor idium

and the r isk was ver i f ied by posit ive oocysts detect ions at only six

abstract ion points serving the following treatment works, Aysgarth, Ir ton,

Keldgate, Richmond (YKS). None of these groundwater works exhibited a

turbidity value higher that 1NTU in 2015.


24

Table 10: Cryptosporidium risk assessment and monitoring of

groundwater abstraction points in the Northern region in 2015

Company

Number of raw water monitoring points where data

submitted

Number of abstraction

points where raw water is

monitored for Cryptosporidium

Number of abstract ion points

where risk of Cryptosporidium was

verif ied* by the detect ion of oocysts

Dee Val ley Water

1 1 0

Har t lepool Water

18 13 0


19 12 0


37 6 0

Yorkshire W ater 73 7 6

Regional total 148 39 6

Industry total 1,601 420 31

*ve r i f ied means e i ther pos i t i ve de tec t ion o f Cryptospor id i um ooc ys ts or data qua l i t y insuf f i c ient . Unc lear data i s assumed to be pos i t i ve .

Surface water works

Turbidity in surface water is related to sediment and biological matter.

Fol lowing rainfal l the f low and hence the turbidity in r ivers and streams

can r ise very quickly and values in excess of 100NTU are not uncommon.

Surface water may be abstracted into reservoirs where storage of the

water allows part ic les to sett le out; however, some of these reservoirs do

not have a suff iciently long retent ion t ime for sett lement of pathogens such

as Cryptospor idium . Al l surface waters are l ikely to contain some faecal

matter originat ing f rom animals, birds and sewage works discharges. For

this reason, surface water must be prepared for disinfect ion (clar if icat ion

and f i l t rat ion). The Bouchier report recommended continuous turbidity

monitor ing af ter f i l t rat ion at surface water works against a performance

target for each individual f i l ter of <1NTU. Since turbidity can interfere with

the eff iciency of disinfect ion, it is a crit ical control measure that should be

val idated by continuous on- l ine monitor ing of f i l tered water with alarms set

to ensure that act ion is taken to ensure that turbidity in water entering the

f inal dis infect ion stage is <1NTU at al l t imes. Where a r isk f rom

Cryptosporidium has been identif ied in the catchment upstream of the

abstract ion point, then companies should be carrying out monitor ing of the

raw water and this should be taken into account when determining the

nature of the r isk and the suff iciency of the control measures.

Table 11 i l lustrates the potential surface water Cryptospor idium r isk in the

region and compares it to the actual Cryptosporidium r isk in 2015. Out of a

Northe rn reg ion

25

total of 161 surface raw water abstract ion points where data were

submitted, 112 were subjected to r isk -based monitoring for

Cryptosporidium and the r isk was ver if ied by posit ive oocysts detect ions at

83 abstract ion points serving the following treatment works:

Boughton, Llwyn Onn (DVW), Broken Scar, Byrness, Fontburn, Gunnerton,

Honey Hil l, Horsley, Lart ington, Lumley, Mosswood, Otterburn, Warkworth,

Wear Valley, Whitt le Dene (NNE); Ashworth Moor, Br idge End, Buckton

Cast le, Buttermere, Clough Bottom, Cowpe, Cumwhinton, Denton,

Ennerdale, Wybersley, Franklaw, Haslingden Grane, Hodder, Hunt ington,

Hurleston, Lancaster, Laneshaw, Loveclough, Mitchel ls, Oswestry, Paddy

End, Piethorne, Quarry Hi l l , Ridgal ing, Ridgegate, Rivington , Sutton Hal l,

Sweetloves, Ulpha, Watergrove, Waterhead, Wayoh, W ickenhal l,

Worsthorne (UUT); Acomb Landing, Albert, Chel low Heights, Eccup,

Elvington, Embsay, Fixby, Graincl if fe, Headingley, Holmbridge, Huby,

Ingbirchworth, Lof tsome Bridge, Longwood, Rivelin, Ruswarp, Sladen

Val ley, Thornton Steward, Tophil l Low (YKS).

Out of these surface water works, f ive exhibited a turbidity value higher

than 1NTU in 2015; Fontburn, Gunnerton (NNE), Chellow Heights,

Thornton Steward, Tophil l Low (YKS) .

Table 11: Cryptosporidium risk assessment and monitoring of surface

water abstraction points in the Northern region in 2015

Company

Number of raw water monitoring points where data

submitted

Number of abstraction

points where raw water is

monitored for Cryptosporidium

Number of abstraction points

where risk of Cryptosporidium was

verif ied* by the detect ion of oocysts

Dee Val ley Water

2 2 2

Har t lepool Water

0 0 0


28 22 15


61 54 39



Industry total 428 274 208

*ve r i f ied means e i ther pos i t i ve detec t ion o f Cryptospor id i um ooc ys ts or data qua l i t y insuf f i c ient . Unc lear data i s assumed to be pos i t i ve .

For Fontburn works (near Morpeth) there were three turbidity fai lures in

the year. Northumbrian Water report that two of these were due to the


26

failure of a valve and a transducer on newly refurbished f i l ters. The

company were recommended to improve their maintenance act ivit ies. The

third failure occurred at the t ime of the instal lat ion of a secur i ty k iosk, but

the company did not identify the cause. The failure at Gunnerton works

near Hexham was identif ied to be associated with corrosion of the outlet

main f rom the works and undertook to replace the main, in associat ion with

other capital investment at the site. The main was commissioned in

October. Subsequently there were two further turbidity failures in

December. The company has init iated a camera survey of all pipework post

f i l ters with the intent ion of identifying sections for replacement . Both these

works wi l l be taken into account dur ing the Inspectorate’s progra mme of

technical audit .

Out of the four failed samples for Yorkshire Water, the company fai led to

identify causes for Tophil l Low No 2 (Kingston upon Hull ) ; and Chel low

Heights (Bradford). However, following the second failure at Chel low

Heights the company replaced the sampling facil i t ies. The failure at

Thornton Steward (Bedale) was attr ibuted to a build -up of aluminium

coagulant and the sampling point was moved to a more appropriate

posit ion. Again, these works wi l l be taken into account during the

Inspectorate’s programme of technical audit .

Coliform bacteria at service reservoirs

Testing for coliform bacteria gives reassurance that the qual i ty of water

held at these strategic points in the distr ibut ion system is adequately

maintained. The national standard requires that at least 95% of no less

than 50 samples collected f rom each service reservoir throughout one year

are f ree f rom all coliform bacteria. In 2015, al l 911 service reservoirs

( including water towers) in the region met the standard.

During 2015, there was a failure for col iforms (>100/ml) at Skelton service

reservoir (NNE). The company found both ingress and a problem with the

sample point. Following a new roof membrane and replacement of the

sample point the reservoir was sat isfactori ly retu rned to supply. There

were two col iform fai lures at Bradley no 2 reservoir (YKS) near Skipton in

August. Investigatory sampling conf irmed the presence of coliform bacteria

at the reservoir as wel l as in downstream distr ibut ion propert ies. Al l

samples upstream from the supplying works were clear of any col iforms.

The failures were reported as an event (see Annex 3) and the reservoir

was removed from supply for a comprehensive invest igation. No cause was

found and since returning to service in November there have been no

further failures.

Northe rn reg ion

27

A col iform bacteria fai lure at Prenton Lower service reservoir (UUT) near

Birkenhead in September resulted in the sample tap being replaced. The

reservoir is subject to a legally-binding Notice requir ing act ion to address

ingress (see Annex 4). The reservoir is unable to be removed from supply

as there are no alternative means of supply, and so capital works are

required to provide such means before the ingress can be resolved. The

company is undertaking enhanced microbiologic al sampling and chlor ine

surveys at the site for the period of the Notice to assure of continued

satisfactory water qual ity. Al l works are due to complete by 2018.

Companies are expected to priorit ise those reservoirs which cannot be

removed from supply to ensure situat ions such as this are avoided.

There was one other reservoir (UUT) which had a single detect ion of

col iform bacteria in 2015, which had previous coliform detect ions since

2003 to which no cause was found. Downham service reservoir near

Cl itheroe, was taken out of supply in January for an inspection. Ingress

was ident if ied through the inlet access hatch cover and a roof to wal l jo int.

There was also a faulty non-return valve on the out let pipework.

The Inspectorate has noted that col iform bact eria were found in 22

samples f rom service reservoirs in the Northern region during the year and

this information wi l l be taken into account during the Inspectorate’s r isk -

based programme of technical audit .

E.coli and Enterococci at consumers’ taps

A total of 37,132 consumers’ taps were tested in 2015 for E.coli and just

two were posit ive (1 UUT, 1 YKS). There was no indication, f rom

information gathered by the two water companies, of a faecal

contamination event affect ing other propert ies in these zone s.

Like E.coli , the presence of Enterococci is indicat ive of faecal

contamination and neither bacter ium should be found in any sample. In

2015, the companies carr ied out 2,939 tests for Enterococci at consumers’

taps. Only four samples, each in a dif ferent zone (3 NNE, 1 UUT) were

posit ive. There was no indication, f rom information gathered by the two

water companies, of a faecal contamination event affect ing other

propert ies in these zones.

The E.col i failure reported by United Ut i l i t ies in the Car l is le a rea was

assessed as being due to poor hygiene at the consumer ’s tap following

posit ive tap swabs from the property. A f it t ings inspection did not identify

any other inf luence.

No cause was ident if ied for a failure in the Holme Val ley area for Yorkshire

Water. The company conf irmed the water quality f rom the assets supplying


28

the area and was not able to f ind a cause for the fail ing sample despite a

f it t ings inspect ion.

Northumbrian Water col lected three water samples (Wylam, Whit ley Bay

and Yarm areas) on the same day which al l failed for Enterococci. The

locations were al l dif ferent parts of the supply system and the company

conducted an audit of the laboratory to ensure that there had been no

cross contaminat ion of samples. The audit found the results to b e genuine,

but no other cause at any of the three propert ies were found. A f it t ings

inspect ion was only possible at one property as the owners refused an

inspect ion at the other two propert ies. I t is essent ial that companies make

al l efforts to fully investigate water qual ity and protect public health .

A sample col lected by United Ut i l i t ies in the Blackburn area was posit ive

for Enterococci, which was demonstrated to be due to the poor hygienic

condit ions associated with the consumer ’s tap with coliforms detected on a

pre-disinfect ion tap swab, but al l c lear af ter dis infect ion of the tap.

Chemical quality

The drinking water regulat ions set out the minimum test ing requirements

for all chemical and physical parameters. A full summary of the results of

test ing by each company, including the results for indicator parameters , is

provided on the DWI website.

The following text and Table 12 set out the results for those parameters

where there has been a failure to meet a European or national standard

(mandatory qual ity standards) and any other parameter of interest. In

addit ion, at the request of local author it ies, the results of test ing for

f luoride, iron, lead, manganese, nitrate, nitr ite, pesticides and radioact ivity

are given. The Inspectorate has also included instances where residual

chlorine results were reported at a level that may be considered

undesirable on grounds of consumer acceptabil i ty (2mg/l).

Northe rn reg ion

29

Table 12: Chemical and physical parameters

The number of tests performed and the number of tests not meeting the standard or specification

Parameter

Current standard or

specified concentration

1

Total number of tests

Number of tests not meeting

the standard

Additional information

Aesthetic parameters

– odour No abnormal

change

10,112 22 UUT (17), YKS (5)

– taste 10,122 25 DVW (1), HPL (1), UUT (20), YKS (3)

Aluminium 200μg/l 13,260 5 UUT (3), YKS (2)

Ammonium 0.5mg NH4/l 10,439 1 NNE (1)

Benzo(a)pyrene 0.01μg/l 3,160 1 UUT (1)

Chlorine – residual (free)2 2mg/l 37,195 2 UUT (2)

Chlorine – residual (total)

2

2mg/l 36,968 4 UUT (4)

Fluoride 1.5mg/l 1,856 1 HPL (1)

Iron 200μg/l 13,261 39 NNE (9), UUT (15), YKS (15)

Lead 10μg/l 2,909 11 DVW (1), NNE (3), UUT (5), YKS (2)

Manganese 50μg/l 13,244 8 NNE (1), UUT (6), YKS (1)

Nickel 20μg/l 2,908 5 UUT (1), YKS (4)

Nitrate 50mg/l 3,477 0

Nitrite 0.5mg/l 3,477 0

Pesticides – total 0.5μg/l 1,737 0

Pesticide – individual3 0.1μg/l 43,854 12

2 4-D (Total) YKS (1), Metaldehyde NNE (1), YKS (9), Mecoprop-P YKS (1)

pH (Hydrogen ion) 6.5 – 9.5 13,357 1 NNE (1)

Radioactivity

Gross alpha4 0.1Bq/l 602 4 UUT (4)

Gross beta4 1.0Bq/l 602 0

Total indicative dose 0.1mSv/year 4 0

Tritium 100Bq/l 39 0

Sulphate 250mg SO4/l 1,803 0

Turbidity (at consumers’ taps)

4NTU 13,366 1 UUT (1)

Notes: 1For comparison, 1mg/l is one part in a million; 1μg/l is one part in a thousand million.

2The value of 2mg/l at the consumer’s tap is a screening value set by the Inspectorate.

3A further 3,552 tests were done for aldrin, dieldrin, heptachlor, heptachlor epoxide, all of which met the

relevant standard of 0.03µg/l. 4These are screening values to trigger action. The standard is ‘Total indicative dose’.


30

Aesthetic parameters

Aesthetic parameters: Taste and odour

Consumers expect their dr inking water to be clear and bright in

appearance and free from discernible taste or odour. In recognit ion of this

the Regulat ions st ipulate national standards for colour, odour and taste.

Companies are required to investigate the cause of any adverse result .

In 2015, a total of 25 samples f rom consumers’ taps in the region exhibited

a posit ive taste or odour. All tests in the region met the standard for

colour. The posit ive detect ions of taste and odour are summarised below

in relat ion to their nature and cause as determined by the investigations

carr ied out by the companies. From this information it can be seen that

many were conf ined to a single property and did not ref lect a wider

problem in the water supply zone.

Penci l: two (1 DVW, 1 YKS): this descriptor is specif ic to a

substance associated with unapproved plast ic pipe and the remedy

is to advise the householder to replace the pipe with approved

medium density polyethylene pipe . These failures occurred in August

at propert ies located in Newton (DVW) and Picker ing (YKS). In both

cases resamples were satisfactory and advice was given to the

customer.

Bit ter/Flat: one (UUT): these descr iptors mostly relate to samples

where the tap water was art if icial ly sof tened; the remedy is to advise

the householder to draw water for drinking and cooking f rom the tap

connected direct ly to the mains (or to f it a mains fed tap if one does

not exist). However, in the single failure in Northwich (July) trace

levels of a harmless plast ic iser were found, but the company

discounted the compound as a cause for the taste. No other cause

was ident if ied and the customer refused access for water f it t ings

inspect ion, although resamples f rom the property were clear.

Earthy/Musty: 11 (8 UUT, 3 YKS) these descriptors relate to

situat ions where harmless, but object ionable, substances are

produced by the growth of algae in raw water storage reservoirs, or

the growth of fungi in poor ly designed plumbing systems . The

remedy is improved treatment/reservoir management by the company

or to advise the householder on necessary changes to the design

and maintenance of the plumbing system. Six of the earthy/musty

failures reported in 2015 by United Ut i l i t ies are discussed in the

Geosmin and methylisoborneol sect ion. The remaining f ive failures

at consumers’ taps in Haydock (Apri l) , Loxley (June), Hull and

Skipton (July), Watergrove (August) were isolated occurrences.

Fol low-up samples were satisfactory in al l cases. For the sample at

Northe rn reg ion

31

Haydock (UUT) a f it t ings inspect ion was not agreed to by the

customer, but the company ident if ied that there was poor turnover in

the local distr ibut ion system. A new connection was made in order to

increase local f lows which were control led with a new pressure

management valve. Yorkshire Water were crit icised for their

investigations at propert ies in Hull and Skipton for not analysing the

samples for any organic chemical analysis and were recommended

to conduct appropriate investigations. While sat isfactory resamples

were col lected f rom Watergrove, Hul l and Loxley , occupants in

propert ies in Watergrove and Loxley refused access for the

companies to carry out water f it t ings inspections. Companies are

reminded that inspections are required for all unexplained fai lures, if

necessary using their powers of entry.

Fruity: s ix (UUT): When United Ut il i t ies detected a f ruity taste or

odour in dif ferent consumer tap samples in two separate zones

(Haweswater (March) and Rainhi l l (Apr il) ) GCMS analysis was used

to help ident ify the cause. At Haweswater, the taste and odour

related to a solvent that can be found in a range of household

products and was at very low concentrat ions. The solvent was

repeatedly detected, but the company was decl ined access for a

f it t ings inspect ion. At Rainhil l t race levels of tr i - and tetra-

chloroethane were detected. These solvents are widely distr ibuted in

the environment and do not pose a concern to health at the

concentrat ions found. Due to the very low levels detected the

company did not identify the solvents to be the reason for the taste

and odour. However, the consumer did not allow a f it t ings

inspect ion. The taste or odour in the Martholme Gravity zone in

September was not present in resamples and a water f it t ings

inspect ion did not identify a cause. No cause either was identif ied

for failures at Newton Heath (June), Warrington West (July) and

Lancaster/Galgate (August). Al l three propert ies were refused

access for a f it t ings inspect ion. Again, companies are reminded that

they have a duty to resolve unexplained fai lures and the

Inspectorate expect that concerted efforts are made to communicate

posit ively and persuasively with consumers to ensure satisfactory

domestic pipework and f it t ings.

Burnt: two (UUT): This descriptor is unusual. One sample, f rom a

property in Old Trafford (August) , also failed for iron and manganese

and the taste and odour may have been associate d with these

parameters. The company were repair ing a mains f itment at the t ime

and they reported that hydraul ic changes within the main may have

contr ibuted to the fai lures. Resamples were satisfactory, but were

delayed by one month due to taste and odour analysis not being


32

scheduled on samples col lected at the t ime of the repair. The

company has been crit ic ised for a failure in conduct ing an

appropr iate investigation. The other sample was f rom a property in

the Stocks Direct zone (December) . The resamples were

satisfactory, but there were also delays associated with this

investigation as well . I t is essential that companies comply with

Regulat ions 17 and 18 which require full invest igations to be made

in a t imely manner. In addit ion the company were again unable to

conduct a water f it t ings inspection.

Plast ic: one (YKS): Such a descr ipt ion could be associated with

plast ic mains or pipework. The sample was col lected f rom a property

in Br ighouse (July), but no cause was identif ied. The main was

f lushed and resamples were satisfactory.

Chlorinous: three (UUT): All dr inking water has a small chlorine

residual as a del iberate process to maintain wholesomeness within

the distr ibut ion system after disinfect ion. Samples should not display

any chlor inous taste and odour as the analyt ical method employs a

step to dechlor inate the water. United Ut i l i t ies addressed the issue

with the analyt ical laboratory for the f irst sample f rom a property in

Northern Moor zone (January). However, further failures f rom Poaka

Beck and Kersal (October) did not produce the same response in the

laboratory. All resamples were satisfactory. These results may

indicate that the analyt ical methodology is not being followed and

this wi l l be taken into account dur ing the Inspectorate’s programme

of technical audit .

Other: one (HPL): No adequate descr iptor was provided for this taste

failure. Hart lepool Water were cr it ic ised for a month’s delay in

col lect ion of the resample and also for not analysing the sample for

organic compounds, which may have caused the taste or odour.

From a public health perspect ive it is a fundamental requirement for

companies to respond in a t imely manner for both the collect ion of

water samples and appropr iate analysis to ensure a satisfactory

outcome for consumers.

Consumer contacts to water companies for taste and odour

When consumers experience a persistent taste or odour, they may contact

their water company to report the problem. Records of these contacts in

each zone are recorded by water companies and passed to the

Inspectorate annually. Figure 13 shows the zone by zone contact rate per

1,000 populat ion across the Northern region. In 2015, three zones

(Bowscar, Hart lepool Wynyard and Plemstal l) stand out as exhibit ing a

contact rate wel l above the nat ional average of 1.6 per 1,000 populat ion.

Northe rn reg ion

33

In the Bowscar zone (UUT) the contacts are also excessive for chlor ine

(see Figure 14), which may indicate the need for the company to review its

residual chlor ine pol icy and/or management. For Yorkshire Water there are

a general ly elevated number of contacts to the east of their region, many

of which are also associated with higher chlorine contacts (for example

Easingwold, Pickering, Dr if f ield, Selby and Holderness).

United Ut i l i t ies has a legal ly-binding scheme in place to address r isks f rom

taste and odour at its Clough Bottom, Loughclough and Sweetloves works

al l of which are on target with work progressing throughout AMP 6. During

2015, the company completed work at its Denton works where the raw

water source is now subject to addit ional monitor ing with the instal lat ion of

a monitor for algae which wi l l give an early indicat ion of l ikely deteriorat ion

of raw water quality. The on-site granular act ivated carbon f i l ters (GAC)

have also been optimised to attempt to make the removal of taste and

odour causing compounds and any organic matter more effect ive.

Although the Inspectorate has not taken enforcement act ion in the region

regarding taste and odour this year companies are expected to review

consumer contacts and use these to identify areas and operat ional

changes that would improve consumer satisfact ion.


34

Figure 13: Rate of taste and odour contacts per 1,000 people

Aluminium

Aluminium can occur natural ly in some water sources. Also, aluminium-

based water treatment chemicals may be used at surface water works to

aid the process of f i l t rat ion .

In 2015, a total of 13,260 samples were tested for aluminium in the

Northern region. Dee Val ley Water, Hart lepool Water, Northumbrian Water

and Peel Water Networks achieved 100% compliance with the aluminium

Northe rn reg ion

35

standard. Just f ive tests exceeded the standard (3 UUT and 2 YKS) and

none of these were found to be related to process control at the works.

Most of the failures ( three) arose f rom local ised disturbance of histor ic

deposits accumulated in the distr ibut ion network. On one occasion (YKS),

other standards ( iron and manganese) were exceeded at the same t ime.

No cause was found for the high levels of metals, but f lushing the main

resolved the situation. On two further occasions (UUT, Apri l and

September) the failures were l inked to events (see Annex 3).

Ammonium

Traces of these salts occur natural ly in most environmental waters and

general ly the highest levels occur in anaerobic groundwater. Intensive

rearing of farm animals can also give r ise to high levels in surface waters.

Ammonia is a major component of mammalian metabolism, so direct

exposure f rom environmental sources has no health signif icance. However,

ammonia can compromise water treatment (dis infect ion and f i l te rs for the

removal of manganese) and its presence in water may be an indicator of

more serious bacterial, sewage or animal waste pol lut ion. Across the

region in 2015, a total of 10,439 tests for ammonium were carr ied out and

just one exceeded the standard of 0.5mg NH4 / l (1 NNE). The company

concluded that this fai lure was due to overdosing ammonium at Lart ington

works as part of the chloramination dis infect ion process. The dosing rate

was reduced and the company has increased the monitor ing f requency to

gain greater control of the process. Al l resamples were satisfactory.

Companies are reminded that they must continuously operate an adequate

treatment works and this includes the ef fect ive control of the dis infect ion

process.

Chlorine

Chlorine is widely used as bleach and has a long history of use in

circumstances where the maintenance of good hygiene is essential, for

example, food preparation, swimming pools and water suppl ies . In the UK

levels of residual chlorine in tap water are very low, typical ly 0.1 – 0.5mg/l

and rarely exceeds 1.0mg/l in water drawn from taps in premises . This

compares very favourably to the World Health Organisation (WHO) health-

related guide value of 5mg/l.

Water companies are required to measure residual chlor ine whenever

samples are col lected for microbiological analysis . Any abnormal change

in the level of residual chlor ine in a part icular supply must be invest igated.

The Inspectorate checks the act ion taken by companies in relat ion to any


36

chlorine result above 2mg/l at treatment works, at service reservoirs or in

zones. Across the region in 2015, there were four occasions when this

occurred. The causes and act ions taken by the companies are descr ibed

below.

The four abnormal results were recorded by Uni ted Uti l i t ies f rom samples

col lected f rom consumer propert ies in two zones (Altr incham and Old

Trafford). They were al l associated with handheld chlor ine analysers. For

three of the failures the company could offer no explanat ion for the high

results, and the water supply itself was satisfactory for taste and odour.

The fourth high result was ident if ied as operator error. The company report

they are implementing an automatic not if icat ion facil i ty which escalates the

high readings to allow immediate investigations and any remedial ac t ions.

In addit ion to invest igating any abnormal change in the level of residual

chlorine, water companies must also investigate and address any situation

where the level of residual chlorine is not acceptable to consumers.

Companies therefore have in place protocols for receiving, assessing and

recording contacts f rom consumers report ing chlor ine-related tastes or

odours in tap water. Figure 14 maps the chlorine taste and odour

consumer contact rate per 1 ,000 populat ion for all zones in the Northern

region dur ing 2015.

Northe rn reg ion

37

Figure 14: Map il lustrating rates of chlorine-related consumer

contacts to water companies per 1,000 population

From Figure 14 it can be seen that consumers in the Bowscar and

Hart lepool Wynyard zones exhibit a relat ively h igh rate of report ing

chlorine-related tastes and odours (>1.9 per 1,000 populat ion) and this is

well in excess of the industry average of 0.2 per 1,000 populat ion. This

information wi l l be taken into account dur ing the Inspectorate’s forward

programme of technical audit in the region.

Fluoride

Traces of f luoride occur naturally in many water sources, part icularly in

groundwaters. In this region, this occurs in United Uti l i t ies and Hart lepool

Water. Consumers can obtain specif ic information on the level o f f luoride

in the dr inking water supply to their home or workplace f rom their water


38

company. Fluoride is not removed by conventional water treatment. Some

companies f luor idate water suppl ies when required to do so by the local

public health author i ty as a protect ion against tooth decay. In 2015, all but

one of the 1,856 tests for f luoride taken across the region met the

regulatory standard (1.5mg/l). One sample (HPL) was reported with a

result of 1.6mg/l. The company conf irmed that the blending arrangements

were sat isfactory. Repeat analysis of the original sample f rom the

Hart lepool zone indicated a result of 1.4mg/l.

On 1 Apri l 2013, the Secretary of State for Health became responsible for

exist ing f luoridation schemes via Public Health England, and local

author it ies became responsible for proposing and carrying out consultat ion

on new schemes and extensions to exist ing schemes.

Fluoride is added on this basis to water supplied by Northumbrian Water

and United Ut il i t ies Water. Figure 15 shows levels of f luoride in zones.

Figure 15: Average levels of fluoride in zones

Northe rn reg ion

39

In 2015 the Inspectorate reviewed f luoride data f rom zones covered by

schemes established to art if icial ly f luoridate water. This exercise identif ied

27 zones (12 in the Northern region) where, due to operational blending

arrangements, f luoridated and non-f luoridated water mixes and the water

in the zone does not reliably reach the target level of 1.0mg/l f luoride

required by Publ ic Health England. In general , zones affected in this way

were on the per iphery of larger art if icial ly f luoridated areas. Publ ic Health

England has been made aware of these zones and it is within their remit to

consider and agree any required act ions with water companies. In 2015,

the Inspectorate reviewed and revised th e Code of Practice on Technical

Aspects of Fluoridat ion of Water Suppl ies together with Public Health

England and publ ished the revised version in January 2016 (avai lable on

the website at http:/ /www.dwi.defra.gov.uk).

Geosmin and methylisoborneol

Geosmin and methylisoborneol are natural substances produced by the

seasonal growth of algae, in s low moving surface water . I t gives r ise to a

character ist ic ‘earthy’ or ‘musty’ taste and odour discernible to consumers.

I t is detected by the method for assessing taste and odour.

In 2015, United Ut il i t ies investigated detect ions of a taste/odour in

samples taken in six zones – Ashton East and Clough Bottom (January),

Fishmoor/Earnsdale (June), at Cast le Carrock and Stalybridge (July), and

Parbold (August). Analysis of the water found geosmin or

methyl isoborneol .

At Parbold, geosmin was detected in the resamples f rom the original and

neighbouring propert ies at 2ng/l. The taste threshold for geosmin is 2 to

5ng/l and is subject ive to an individual ’s palate. The company has an

algae management plan for the source water treatment works (Rivington

works), but because the level was below their threshold l imit no further

act ion was taken. There was no other cause identif ied for the musty taste.

The same situat ion was exper ienced at Stalybridge in that low levels of

geosmin and methyl isoborneol were detected, but they were below the

act ion threshold within the algae management plan. The works relat ing to

this water is Buckton Castle. Since this t ime sampling off icers have ca rr ied

out qual itat ive taste and odour analysis at the source works on every vis it .

At Cast le Carrock works it was ident if ied that the previous week geosmin

concentrat ions were detected at 11ng/l. The on -site taste and odour

test ing had not ident if ied any taste or odours. In response the dose of

powdered act ivated carbon (PAC), to absorb and reduce the compound,

was increased in accordance with the site -specif ic algae management

plan.


40

Both geosmin and methyl isoborneol were detected at Fishmoor and Hodder

works which were supplying the Fishmoor/Earnsdale zone at the t ime of

the original taste or odour failure. The company immediately progressed

work to install PAC dosing r igs at both sites.

At the t ime of the failed sample for the Clough Bottom zone, the source

water was f rom Haslingden Grane works. For most of the month of

January, due to a planning error , no samples were col lected for geosmin or

methyl isoborneol . Resamples col lected at the t ime were satisfactory for

taste and odour, but no cause was ident if i ed for the failure. Neither was a

cause identif ied for the sample f rom Ashton East zone. Resamples were

satisfactory and there had been elevated levels of geosmin detected in the

raw water at Buckton Castle works leading up to the failure, but the levels

were below detect ion in the resamples. The Inspectorate would expect

companies to keep any taste or odour management plans under regular

review and to amend as appropriate to take account of anomalies.

Lead

Lead in tap water typical ly ar ises in premises where the pipes and brass

f it t ings have not been refurbished since the 1970s when the use of lead in

contact with dr inking water was banned. The other reason why lead may

be found in tap water is the i l legal use of lead-based solder for making

joints on copper pipes.

In addit ion to the ban, the standard has been progressively t ightened from

50µg/l in 1990 to 25µg/l in 2004 and since the end of 2013 has stood at

10µg/l. Dur ing this t ime water companies have assessed the r isk of lead

being present in tap water at the point of use and, where necessary,

instal led addit ional water treatment (general ly phosphate dosing or pH

correct ion) to minimise the propensity of lead to leach out of pipes and

f i t t ings within consumers’ premises.

Since the only permanent long-term solut ion to the issue of lead in tap

water is the removal of lead pipes and f it t ings, water companies have been

engaged in a range of other act ivit ies to identify where specif ic act ion

plans for lead removal are required, for example , in social housing or

schools. I f a lead failure occurs in a public bui lding then water companies

and local authorit ies are able to use their powers to require the owner to

remedy the problem; however, in relat ion to private property, water

companies and local authorit ies can only give advice, they cannot compel

homeowners to replace lead pipes or f it t ings.

Figure 16 shows the posit ion of the Northern region in relat ion to the

industry as a whole. I t can be seen that the region has matched or

exceeded the industry f igure for the last six years.

Northe rn reg ion

41

Figure 16: Percentage of tests meeting the standard of 10µg/l for lead

between 2006 and 2015

In 2015, companies in the Northern region reported 11 failures (DVW 1;

NNE 3; UUT 5; YKS 2) of the standard of 10µg/l out of a total of 2,909

tests.

Most (9 out of 10 domestic propert ies) of these failures occurred in zones

where the water is treated with phosphate to reduce the r isk from lead.

Companies are expected to use information about the locat ion of failures

at domestic premises to ensure that water treatment is opt imised and to

identify where new water treatment provision is required. Appropriate

advice was provided to al l nine householders. The one household that was

not in a zone treated for plumbosolvency (NNE) was within a zone wh ich

had previously undergone a lead pipe replacement scheme. However, this

property had not benef ited f rom the act ivi ty. The company replaced the

communication pipe and advised the customer to replace their service

pipe.

Lead above 10µg/l was found in one sample col lected f rom a public

bui lding (UUT). The company made numerous attempts to collect further

samples and contact the owners of the community centre in Worsthorne to

complete a water f it t ings inspect ion without success. The Inspectorate was

minded to enforce that the company use their powers of entry to resolve

the situation. Subsequently the company were informed that the premises

was closed to the publ ic for refurbishment, at which t ime the lead pipework

within the premises was replaced, which was latterly conf irmed by the

company.


42

Nickel

Nickel may be present in coatings on modern tap f it t ings. In 2015, a total

of 2,908 tests were carr ied out for nickel and all but f ive (1 UUT, 4 YKS)

met the standard (20µg/l).

A level of 29.7µg/l nickel was reported in a sample f rom a consumer’s tap

in Smallwood zone. The invest igation by United Ut i l i t ies Water ident if ied

the cause to be due to the tap and of fered advice to the owner. One of the

failures (61.9 ug/l nickel) in the Leeds area for Yorkshire Water was not

l inked to a cause, whereas investigations for the remaining three failures

(Leeds, Cl if ton and Loxley) ident if ied the tap as the cause. In al l cases

advice or replacement taps were offered to the customer.

Pesticides and related products

This group of substances, generically cal led pesticides, includes many

organic chemicals ranging from weed kil lers, to insectic ides and

fungicides. Water sources may contain traces of pestic ide residues as a

result of agricultural use (pest control on crops) and non -agricultural use

(herbicides for weed control on highways, railways etc.). Water companies

are required to assess the r isk to drinking water supplies of pestic ide use

in source water catchments and then test for those that might be present.

Companies have taken raw water monitor ing into account when

document ing potent ial and actual pesticide hazards through thei r

Regulat ion 27 r isk assessments . When pestic ides are f irst detected, water

companies wi l l enhance the monitor ing of raw water and not ify the

Environment Agency to facil i tate appropriate act ion in the catchment to

safeguard drinking water quality.

Table 17 i l lustrates the potential pestic ide r isk in the region and compares

it to the actual pesticide r isk in 2015. Out of a total of 404 raw water

monitor ing points, 223 were subjected to r isk-based monitor ing for

pestic ides and the r isk was ver if ied by posit ive detect ion of pestic ides at

only 34 abstract ion points.

Northe rn reg ion

43

Table 17: Raw water monitoring points at risk from pesticides in 201 5

Company Number of raw

water monitoring points

Raw water monitoring points

monitored for pesticide risk

Number of raw water monitoring points

where pesticide risk verif ied by monitoring

Dee Val ley Water

3 2 1

Har t lepool Water

19 19 0


71 38 4


127 67 9



Industry total 2,553 1,506 229

Data a re f or raw wate r moni tor ing po in ts in the reg ion in 2015. Ve r i f i ca t ion o f r i sk i s based on a t leas t one sample conta in ing pes t ic ide abo ve the l im i t o f detec t ion.

The outcome of pesticide r isk management by companies in the Northern

region was that there were only 12 pesticide failures recorded by two

companies (1 NNE, 11 YKS) dur ing 2015. The circumstances are

summarised below.

2,4-D

2,4-D is a phenoxy acid herbicide used for k il l ing broad- leaved weeds in

cereal crops, turf , forestry, orchards and non -crop areas. The standard is

0.1µg/l.

In May, Yorkshire Water detected 2,4-D at a level of 0.152μg/l in a sample

f rom Ingbirchworth works (near Holmf irth). The works is supplied f rom two

raw water reservoirs: Royd Moor and Ingbirchworth. Fol lowing the

pestic ide detect ion the company increased the abstract ion f rom Royd

Moor, which had lower levels of pesticide, and reduced the f low from

Ingbirchworth reservoir. In addit ion the treatment for pesticides (powdered

act ivated carbon) was optimised with an increase in the carbon dose, and

the company increased monitoring f rom monthly to fortnightly. The farmer

responsible for the pestic ide appl ica t ion was also engaged and reminded

of his responsibi l i ty (via a tenancy agreement) to seek agreement when to

apply the pestic ide, which was appl ied immediately before heavy rainfal l.

Due to the knowledge associated with the reason for the failure of this

pestic ide, together with the remedial act ion, it is considered unl ikely to

occur again and so no legal instrument has been necessary.


44

Mecoprop-P (MCPP)

Mecoprop-P is a herbicide f requently found with other herbicides such as

2,4-D or dicamba. I ts predominant use is for weed control in lawns,

amenity agriculture and cereals. The standard is 0.1μg/l.

In May, mecoprop-p was detected at a level of 0.13μg/l in a sample f rom

Ir ton works (near Scarborough). The company, Yorkshire Water, has a

pestic ide Not ice in place to mit igate the r isk based on catchment

management act ivity , due for complet ion in December 2018.

Metaldehyde

Metaldehyde is the act ive ingredient in some slug pel lets. The standard is

0.1µg/l.

Throughout the period November to December metaldehyde exceeded the

standard on ten occasions (NNE 1, YKS 9) at levels up to 0.218µg/l. The

failure for Northumbrian Water followed an extreme f looding event at the

Horsley works near Prudhoe. The company monitor the inf lows to Whitt le

Dene reservoir as wel l as the River Tyne for metaldehyde and derive an

appropr iate blend of these waters to avoid exceedances. The f looding

forced the cessation of r iver water pumps and so only Whitt le Dene

reservoir water could be used to maintain supply, losing the blending

effect of the r iver water. The company has since achieved a Safeguard

Zone status for the reservoir catchment, with an act ion plan in place which

includes sustained engagement with the farming community.

Al l the metaldehyde failures for Yorkshire Water were either at consumers ’

taps or supply points served by three works (Lof tsome Bridge, Elvington

and Irton) where the company has legal ly -binding programmes of work to

carry out catchment management investigations throughout the AMP6

period and to develop long-term solut ions in their high r isk catchments by

March 2020.

pH (Hydrogen ion)

The acidity of water is measured by pH. The standard for pH requires it to

be above 6.5 and below 9.5. The most f requent problems arise in upland

areas where water may pick up iron and humic acids f rom peaty soi l,

result ing in acidic raw water ( low pH), which is commonly described as

‘sof t water’. Such water has an increased potential to corrode iron pipes.

Where pH values above 9.5 occur this is usual ly due to leaching f rom

cement mortar- l ined mains. Addit ionally, the pH of water can be affected

when a treatment device within premises art if icial ly sof tens the tap water.

Northe rn reg ion

45

In the Northern region, out of a total of 13,357 tests, the standard was

exceeded on one occasion in 2015.

Northumbrian Water reported a sample f rom Tyneside East zone with a pH

of 6.2 in March. The investigation failed to identify a cause. The company

demonstrated satisfactory performance from the associated treatment

works and other samples taken from the zone fo r a two-month period pr ior

to the failure. Al l resamples were satisfactory .

Radioactivity

Gross alpha/gross beta/total indicative dose

Radioactivity in raw water can occur natural ly in the environment or f rom a

specif ic point source emission. Water compan ies are required to screen for

radionucl ides that emit either alpha or beta part ic les. I f such screening

exceeds guide values (Gross alpha 0.1Bq/l, Gross beta 1.0Bq/l) then fuller

analysis for specif ic radionucl ides is carr ied out to determine the origin.

Under these circumstances the total indicat ive dose (TID) must be

calculated. TID is a measure of the effect ive dose of radiat ion through

consumpt ion of the water and no further act ion is required if the guide

value of 0.1mSv/year is not exceeded.

Where screening and other information has shown there to be no r isk

relat ing to radioact ivity in a specif ic water supply, companies can apply for

and have been granted, an exemption f rom further radioactivity monitor ing

(known as a waiver) by the Inspectorate. In 2015, a waiver was renewed

for TID and tr it ium for 32 works operated by United Uti l i t ies and a new

waiver for tr it ium was granted for six works operated by Dee Val ley Water,

three of which supply the Northern region (Boughton, Llwyn Onn and

Plemstal l works).

In 2015, the two companies (DVW, UUT) in the region that carr ied out

radioact ivity monitor ing conducted a total of 1,204 tests. There were four

(UUT) results that exceeded the gross alpha or gross beta screening

values. The elevated screening values occurred at the following works:

Lightshaw (3) and Royal Oak (1).

United Ut i l i t ies have demonstrated that the TID is below the guide value of

0.1mSv/year at the Royal Oak works and no further act ion is required. For

Lightshaw the company has fol lowed guidance and found the act ivity is a

result of naturally occurring radioact ive species of uranium and radium, at

levels that are not harmful to health with a TID value of 0.013mSv/yr. The

company continue to monitor the gross alpha concentrat ions for any

abnormal change that would init iate a further TID assessment to be

undertaken.


46

Tritium

Monitor ing for tr it ium is necessary only where a source of tr it ium is present

within the catchment and it cannot be shown on the basis of other

surveil lance programmes or inves tigations that the level of tr it ium is well

below its parametr ic indicator value of 100Bq/l.

In the Northern region, the following companies monitor for tr it ium; Dee

Val ley Water, Peel Water Networks, United Uti l i t ies. Together these

companies analysed 39 samples for tr it ium in 2015 and none of them

breached the parametric indicator value.

Monitor ing waivers t ime expire af ter f ive years and the Inspectorate has

been in discussion with companies to ensure they are now carrying out

monitor ing in those situat ions where a waiver had not been renewed.

The EU Counci l Direct ive made under the Euratom Treaty came into ef fect

in October 2013. The Direct ive sets out the requirements for the protect ion

of the health of the general publ ic with regard to radioactive sub stances in

drinking water. In England the Inspectorate has been working closely with

Defra to ensure that the necessary changes are made to the 2016 dr inking

water qual ity regulat ions. The principal change introduces new

requirements for radioactive parameters, in part icular the indicator

parameter radon, with its own monitoring requirements. The other

requirements already being in place.

The Inspectorate commissioned a project to understand the implicat ions of

the EC’s proposals relat ing to radon in dr inking water in the UK and the

report may be found on the Inspectorate’s website. In May 2015, the

Inspectorate publ ished the requirement for companies to carry out r isk

assessments for radon in al l of their catchments and to begin regulatory

monitor ing for radon from 1 January 2016 where the r isk is considered to

be moderate or high or unti l r isk assessment shows there to be no or low

risk and monitoring can cease.

Sulphate

The level of natural ly occurring sulphates in water is highly variable and

normally ref lects the local geology with greater amounts tending to be

found in brown coal regions and in coastal areas. The f inding of an

increased level of sulphates, along with chlor ides, can also indicate human

pol lut ion of a water source. Waters of natural ly hig h sulphate content,

part icularly alkal i and magnesium sulphates, act as a purgative. Even

relat ively small amounts may cause a temporary disturbance to the normal

intest inal function. Higher levels have a tendency to cause diarrhoea,

especial ly among chi ldren. The standard of 250mg/l is set to avoid these

Northe rn reg ion

47

concerns and to assist with the select ion of suitable sources of drinking

water.

In 2015, there were no failures to meet the standard f rom 1,803 tests.

Northumbrian Water has cont inued investigations into a high sulphate

source of water (River Wear, supplying Lumley works). The elevated levels

of sulphate derive f rom an Environment Agency (EA) l icensed groundwater

dewatering (acid mine) discharge. Dur ing low r iver f lows the sulphate

levels are pronounced. Northumbrian Water t r ial led the use of an

alternative coagulant (polyaluminium chloride) at Lumley works during

periods of low f low, which appeared successful at reducing levels of

sulphate. The company wil l repeat the tr ial dur ing 2016.

Maintaining water quality in distribution

Elevated levels of iron or manganese are object ionable to consumers

because the water may appear turbid or discoloured due to unsightly

deposits and may also stain laundry and water f it t ings. Since 2004 the

Inspectorate has been monitor ing the progress of companies’ distr ibut ion

maintenance work, using an index made up of three parameters (turbidity,

iron and manganese). Figure 18 shows the long -term improvements in the

Northern region. In 2015, there was some improvement, but gene ral ly the

region is below the industry average.

Figure 18: Percentage of tests meeting the standards for turbidity,

iron and manganese

Note: Peel Water Networks only began supplying in 2009. They achieved 91.67% in 2009 and 100% in each year since 2010.


48

Discolourat ion of tap water of ten prompts consumers to contact their water

company. The number of people contact ing water companies about

discoloured water is reported annual ly to the Inspectorate in accordance

with Information Letter 1/2006. Looking at the trend since 2008, it can be

seen from Figure 19 that across the industry, the numbers of consumers

contact ing their water company to complain about discoloured water has

fallen f rom 70,648 to 44,141 in 2015. Between 2014 and 2015 in the

Northern region there was a small decrease in contacts for discolourat ion,

with the f igure now standing at 14,170, down from 16,305 in 2014. Overall

the region accounts for 32% of all consumer contacts for discolourat ion

across England and Wales.

Figure 19: Total contacts for discolouration 2008–2015

In Drinking water 2014 , the Inspectorate asked companies to review

consumer contact data on a cont inuous basis to identify zones with

persistent problems that require remediat ion, irrespective of whether the

zone has been the subject of improvement works in the past. In 2015, the

Inspectorate carr ied out the exercise to identify these zones start ing with

where the level of consumer contacts had been above the industry level for

the three preceding years. Discolourat ion of t ap water of ten prompts

consumers to contact their water company indicating a persist ing problem

for consumers. Further work then identif ied six companies in England

where such zones existed, but where no legal instruments were in place.

Legal instruments describe the planned drinking water qual ity

improvements of companies where progress to rect ify the problem can be

monitored against set object ives. The Inspectorate met with the companies

Northe rn reg ion

49

to understand what plans existed in these areas to reduce consumer

contacts for discolourat ion, distr ibut ion compliance failures and water

quality events. Such plans would be expected to include, treatment works

upgrades, reservoir cleaning and carrying out operational measures (such

as f lushing) within zones to help improve distr ibut ion water qual ity.

After reviewing the company plans, customer contact data, compliance

failures and distr ibut ion water qual ity event information the Inspectorate

assessed these plans to see if they al igned with the areas of concern and

were appropr iately targeted to their own performance targets. Where

necessary, the Inspectorate issued new legal instruments to formalise

these operational plans ensuring del ivery of the required improvements for

the benef it of consumers.

From the review, two companies were identif ied as being in the Northern

region, (HPL and UUT). Hart lepool Water is complet ing high velocity

f lushing in 19 high-r isk distr ict meter areas within the Hart lepool zone

which was ident if ied as having high discolorat ion contact rates i n this

exercise. The company is also investigat ing and delivering manganese

removal upgrades at the Dalton Piercy works. In order to ensure the full

del ivery of these programmes, the Inspectorate has init iated enforcement

act ion in the form of zonal Regula t ion 28 Notices in the Hart lepool area.

United Ut i l i t ies has a mains cleaning programme to f lush 53 zones

identif ied as having high discolorat ion contact in this exercise. In order to

ensure the full del ivery of these programmes, the Inspectorate has

init iated enforcement act ion in the form of zonal Regulat ion 28 Notices in

the zones shown in Figure 20. The Regulat ion 28 Not ices also includes

steps for the company to identify and develop a longer -term strategy to

address the discolourat ion r isk in these identif ied zones.


50

Figure 20: Zones where notices have been served to address

discolouration

In 2015, across the whole of the Northern region, out of a total of 43,031

tests for the four parameters ( iron, manganese, turbidity and

benzo(a)pyrene) there were 49 failures (benzo(a)pyrene 1; iron 39;

manganese 8; turbidity 1). The Inspectorate expects that the location and

circumstances of the 49 failures reported by the companies wi l l have been

taken into account during the relevant r isk assessments an d Distr ibut ion,

Operation and Maintenance Strategies, (DOMS). The detai ls of where this

occurred are descr ibed below.

Northe rn reg ion

51

Northumbrian Water – nine failures for iron and one failure for

manganese. These fai lures were most ly around Newcast le upon

Tyne and companies. Two of the failures, both in the Hil lhead zone,

are covered by an undertaking, requir ing the company to make

improvements to the distr ibut ion system. One failure in Blyth was

considered for enforcement due to the protracted f lushing that was

required to overcome the discoloured supply. The zone contains an

unl ined cast iron main. The other failures were treated as isolated

occurrences due to a local ised disturbance of mains deposits, mainly

dealt with by f lushing. The Inspectorate expects that compani es wi l l

keep such situat ions under review within DOMS and update r isk

assessments.

United Ut i l i t ies Water – 15 failures for iron, six failures for

manganese, one failure for turbidity and one failure for

benzo(a)pyrene. These failures were mostly in the s outh of the

company’s area around Liverpool, Manchester and Crewe, and

companies are expected to have taken the data into account during

their r isk assessments and DOMS. Five of the failures occurred in

zones where the Inspectorate served Not ices. Benzo(a) pyrene is one

of f ive polynuclear aromatic hydrocarbons (PAHs) that are monitored

within drinking waters. The main source is f rom the breakdown of

coal-tar coating of cast iron or ducti le iron distr ibut ion pipes. They

have a high aff inity for part iculate matter. Their presence would

indicate the need for a local ised distr ibut ion maintenance

programme. The cause of the benzo(a)pyrene failure f rom a

consumer’s tap in the Hall iwells zone was not establ ished, but the

sample also failed for manganese and iron, which was indicat ive of

disturbed mains deposits.

A failure in Warrington South zone (covered by an undertaking

requir ing United Uti l i t ies to make improvements to its works at

Oswestry by improving performance for manganese removal and also

sustained improvement to the associated distr ibut ion system) was

attr ibuted to damage caused by a third party mechanical digger. The

resultant burst main was repaired, but during recharge of the main

sediments were disturbed and caused discoloured suppl ies. The iron

failure in Simmonds Hil l was due to a pr ivate cast iron pipe, which

the residents were advised to replace. Al l other failures were either

covered by undertakings or isolated occurrence’s and resolved by

mains f lushing.

Yorkshire Water – 15 failures for iron and one failure for

manganese. These fai lures were most ly in the western side of the

company’s area and around Kingston upon Hull and companies are

expected to have taken the data into account dur ing their r isk


52

assessments and DOMS. The iron fai lure in the Hornsea zone was

reported to be due to the condit ion of the ducti le iron main. The

company has reconf igured the local distr ibut ion system to improve

f low through the main, which is being kept under review by the

Inspectorate. Al l other failures were isolated occurrences and

resolved by mains f lushing.

In al l cases the Inspectorate wi l l take this information, the consumer

contact rates and the effect iveness of company strategies into account

during its r isk assessment of companies and, where appropr iate, take

enforcement act ion.

Annex 4 detai ls the legally-binding programmes of distr ibut ion

maintenance work scheduled for complet ion between now and 2020 to

address ongoing distr ibut ion qual ity problems in the region.

Chapter 5: Drinking water quality events

Chapter 5

Explains how events are classif ied.

Provides summary f igures of the number and type of events.

I l lustrates industry-wide learning points f rom case studies.

Water quality events are classif ied into f ive broad categories based on the

init ial company report. The categories are:

Not significant: no further information required by an inspector to assess

the event.

Minor: i t is unl ikely that further information would be required by an

inspector to assess the event .

Significant: a ful l company report is usual ly required to enable an

inspector to assess the event .

Serious: in addit ion to a full company report, the assessment may involve

more than one inspector and site visits in the investigation.

Major: in addit ion to a full company report, wil l require an investigation led

by senior inspectors involving extensive information gathering and usual ly

site vis its.

In 2015, companies in the Northern region notif ied the Inspectorate of

111 events. Table 21 shows how these events were classif ied.

Northe rn reg ion

53

Table 21: Water quality events in the region in 2015

Nature of event

Risk assessment category (DWI)

Minor* Signif icant Serious**

2014 2015 2014 2015 2014 2015

Air in water - - 2 1 - -

Chemical 5 3 - 2 - -

Discoloured water 3 3 13 24 - -

Inadequate t reatment 1 3 6 16 1 1

Loss of suppl ies/poor pressure 2 7 2 4 - -

Microbiological - 2 6 2 - -

Taste/Odour 5 8 7 2 - -

Health concern 2 2 3 4 - 1

Publ ic concern 4 13 5 6 - 1

Other 6 3 4 3 - -

Region overal l 28 44 48 64 1 3

England and Wales 281 322 218 223 12 10 *Minor category numbers inc lude a l l not s ign i f icant and minor events **Ser ious category numbers inc lude a l l ser ious and major events

A summary of the nature, cause and durat ion of each event categorised as

signif icant, serious or major along with detai ls of the Inspectorate ’s

f indings are set out in Annex 3 . Most events were of relat ively short

durat ion and the company took appropriate act ion to inform and safeguard

consumers and other stakeholders. A comparison of 2014 events with

those of 2015 shows an overal l increase in the numbers of signif icant,

serious and major events.

A number of notable recurring themes in the region in 2015 were:

improperly dis infected water due to inappropriate process control issues;

discolourat ion/ loss of supplies due to i nadequate supervision of

contractors; and inadequate r isk assessments prior to rout ine and planned

work. Annex 3 provides further detai ls and while these were addressed via

the events assessment process , companies should cont inue to be

part icularly vigi lant around these themes as they wi l l be taken into account

during the Inspectorate’s r isk -based programme of technical audit .

The region experienced two major events in 2015, both f rom United

Uti l i t ies, at Franklaw works and Sweet loves works. Addit ional ly, for United

Uti l i t ies, there were nine events relat ing to improper ly dis infected water

during the year. Event assessments identif ied that varying themes,

including: poor site-specif ic dis infect ion pol icy; lack of pH control;

inappropr iate process alarm phi losophy; poor escalat ion of events; and

poor maintenance. In addit ion, a recurr ing issue was once a problem . I t

had been ident if ied that the asset had an inef fect ive or absent abi l i ty to

run improperly disinfected water to waste. However, the overarching fai lure

was that the r isk assessment and subsequent mit igat ion or contingency

planning was not evident. The company did not address the r isks

satisfactori ly with the consequence that public health was put at r isk when


54

the systems failed. During the year, as t he events were reported, there

was clear indication that the company were not learning f rom previous

errors. Disinfect ion is a fundamental tenet of water treatment and the

failures that United Uti l i t ies displayed is whol ly unacceptable. The

Inspectorate is continuing to invest igate whether the offence of fail ing to

adequately treat or dis infect water has been committed in respect of two of

these nine events. Legal Instruments have been issued to ensure the

remainder of the failures are resolved. One of the major events is

descr ibed below.

Failure of disinfection control – weakness of asset design and

function

During the year there were two events at Sweet loves works concerning

improperly dis infected water as a result of the loss of pH control in the

dis infect ion treatment stage. Sweetloves works is situated north of Bolton

and supplies just short of 80,000 propert ies. The treatment consists of

coagulat ion, clar if icat ion and pr imary and secondary f i l t rat ion with pH

adjustment at several points before dis infec t ion. The control of pH is

cr it ical to the process so when in both cases, control was lost due to the

failure of a sample pump to the pH meter , the resultant high pH (>pH10)

interfered with the formation of hypochlorous acid for effect ive dis infect ion.

For the f irst event the company decided against isolat ion of the contact

tank due to the length of t ime to operate the isolat ion valves and r isk of

interrupting supply to customers. The company also de cided against the

issue of boil water advice due to the t imescale involved in distr ibut ing

notices and addit ional ly that the raw water quality was within normal

ranges and not indicating any signif icant challenge to the works.

For the second event the company were slow to recognise the same

scenar io, but once real ised, act ively worked to restr ict any further

improperly dis infected water entering supply . The company again decided

that boi l water advice was not required. However, due to the length of t ime

it took to regain control of the treatment process , alternative suppl ies were

insuff icient. The company latterly decided to release the improperly

dis infected water, in associat ion with a boi l water advice, provided the pH

did not exceed 9.5.

Publ ic Health England, as part of their role, wi l l provide advice and

information to the publ ic, professionals and government on health

protect ion issues, based on scientif ic and health protect ion expert ise. The

company consulted with PHE on both occasions and they supported the

decisions for which the company remain responsible.

Northe rn reg ion

55

This event provides a further example of companies fai l ing to prevent

inadequately treated and disinfected water entering supply f rom works and

fail ing to control operational r isks in the l ight of previous events and when

the company is c lear that the control is dependent upon cr it ical equipment.

I t is questionable when the company strategy considers it acceptable not

to put in robust maintenance for something as basic as sampling pumps

compared to the senior decision and business r isk necessary to rec over

f rom events of this size when considering a boi l not ice. Furthermore, why

has the company not considered the design of the contact tank which in its

current state could only be isolated and not discharge any improperly

treated water to waste? Even when the si tuation results in the inevitable

and a boi l not ice is cal led for, why is there not effect ive management and

an effect ive publ ic health protect ion?

Senior managers must be aware and be responsible for water quality and

this must include al l aspects of company operat ions. There must be clear

understanding at the most senior level that r isks are identif ied, works and

assets work within predesigned l imits, the technology is suitable and

robust, and redundancy is bui lt in to crit ical steps; control meas ures are in

place and robust, and those who work in or with the company are

competent to carry out the functions and duties of the company. Senior

managers should expect that the Inspectorate wil l continue to ident ify

those companies who present the greatest r isk to be a focus of attention.

While there was a catalogue of errors in both events, the greatest

weakness was the design. In addit ion, there was the inconsistent approach

to issuing boil water advice, which was symptomatic of pol icy. The

Inspectorate expects companies to have appropr iate design of treatment

assets and robust publ ic health polic ies.

Wider learning points f rom event assessments in the region in 2015 are

highl ighted by the following case:

Secondary events caused by initial event invest igations

Lart ington works near to Darl ington is a large surface water treatment

typical ly supplying 110 Ml/d of treated water to a populat ion of

approximately 580,000 in the Teesdale and Teesside area. The site ,

original ly f rom the 1960s, treats raw water col lected in f ive impounding

reservoirs and consists of two dif ferent clar if icat ion streams, pH correct ion

for manganese removal before rapid gravity f i l t r at ion and f inal ly

dis infect ion.

In August 2015, a single E.col i was detected and as part of the

investigation a remote operated vehicle survey of the contact tanks was

undertaken. This technique al lows companies to inspect tanks and


56

reservoirs for signs of internal damage whil e st i l l in supply. In September ,

in preparat ion for this survey, f low rates on t he site were reduced to al low

the inspect ion to be undertaken. While this in itself is not unusual, due

regard for the operabi l i ty l imits of a works must always be considered and

this should consider not only the upper l imits , but the lower l imits to

determine the hazards and l ikely consequence of an act ion which may

present a r isk. In this works the lower l imit is , in part , governed by the

minimum dosing of l ime which can be achieved by the pumps. When the

f lows were reduced, the works was operating at the minimum possible l imit

for the l ime dosing pumps. When the l ime batch changed to a higher

concentrat ion the pump could not dose any less to compensate for this

change causing the pH to r ise outside the crit ical l imit. The effect iveness

of chlorine used for dis infect ion is part ly based around the pH of the water

it is dosed into. The consequential ef fect of this was for disinfect ion to

drop to less than 30% of the World Health Organis ation recommended

minimum of 15mg.min/l. The company, as a reactive measure, have set the

alarm to 22mg.min/l to ensure there is an earl ier warning of problems,

however, the object ive of r isk analysis is to ident ify proactively condit ions

which may occur based upon historic analysis.

This site was subject to an earl ier event in June where the company

sought to al low the plant to perform more effect ively at low f lows, the

sudden change in f low resulted in a problem with the clar if iers. Whil e this

was not exact ly the same situation, this was an example of the works

being asked to perform outside its operabi l i ty l imits and should have

served to identify the r isk of changes. The question arises therefore as to

why the company had not carr ied out an appropr iate r isk assessment of a

site known to have had recent operabi l i ty problems pr ior to ini t iat ing an

investigation which reduced the output to the minimum possible l imit

el ic it ing an event more serious than the one it was invest igating. Senior

managers should ensure that r isk analysis is transferred to r isk

assessment and this information is taken into account and used to direct

future work which may be carr ied out by staff or contractors who do not

have an overview of the consequential ef fects on treatment processes.

The following examples are included in this report because of the in dustry-

wide learning points.

Issue of a do not drink notice to 17 properties

In May to June, 17 propert ies in the vi l lage of Stoke Goldington,

Northamptonshire were issued with a do not drink not ice when the

company detected polycycl ic aromatic hydrocarbons (PAH) in the water

af ter planned cleaning. PAHs are present in coal tar, a technique widely

used before 1970 to l ine the inside of iron pipes. When the l ining degrades

Northe rn reg ion

57

or is disturbed by cleaning, PAHs can be released into the water result ing

in an unpleasant taste of ten described as similar to white spir i t . The

Inspectorate noted that this outcome was the result of a consumer

complaint dating back three years when she complained her water was the

colour of teabags, lef t a rusty looking residue in the s ink and she could not

use the water supply for drinking, cooking, laundry or washing. The

consumer f inal ly resorted to contact ing the Inspectorate in August 2014

who took up her case on her behalf .

During the period June 2014 – June 2015, the company tr ied: mains

f lushing, air scouring, part ial mains replacement, ice pigging and

eventual ly conducted a complete mains replacement of old cast iron main,

which f inally solved the problems in the local network. Prior to complete

mains replacement of a further 1.4km section in addit ion to the init ial

replacement of 900 meters, the company were st i l l detect ing high levels of

iron to which the company decided to use ice pigging. This is a relat ively

new technique which is becoming more widely used since it s imply us es

crushed ice pushed through the pipe as an abrasive mater ial for cleaning.

I t was this exercise which led to the release of PAHs from a previously

unknown coal tar l in ing. The cleaning was unsuccessful due to a blockage

in the main which had restr icted the effect iveness and the full mains

replacement f inally resolved the matter in June.

There are any number of cr it icisms that could be level led at the company

in this event, not least was the fact that i t was unnecessari ly protracted;

the remedial techniques were poor ly chosen, planned and inappropr iate

given the uncertaint ies of mains materials and potential l in ings present in

an old cast iron main in the area. I t remains, however, that this event may

well have been avoidable had a r isk analysis appropr iate for ice pigging

been ef fect ive. This technique has resulted in a number of events in recent

years and close scrut iny of these events of ten uncovers uncertaint ies of

the company over their own networks and of the appl icat ion of the method.

Companies are reminded to ensure they are familiar with the technique

and to ensure it is appropr iate for the task in hand before use. In this

instance had the company elected to replace the whole main rather than

half of it , the event would never have happened and whi le it is impossible

to understand the exact reasons for the decision at the t ime, a long -term

risk assessment would have ident if ied the removal of all the degraded iron

main as this would have eliminated this event f rom ever happening again

in the future.

Fundamentally, however, this was the fai lure of the company to their

consumers: The consumer who had been complaining for three years;

those consumers who complained of unusual tastes ; and the signif icant

inconvenience and distress to some of the consumers served, whose


58

businesses and social plans were severely disrupted when the event

occurred.

Loss of primary disinfection

In the late hours of 1 October the main chlor ine dosing system at Frankley

works failed. Chlorine is the most commonly used disinfectan t for water

and is used to remove any remaining microbes af ter treatment. An

important process such as this is expected to have a secondary system in

place which starts automatical ly in the event of the main chlorine dosing

system being lost. Such a system exists in Frankley works, but in this case

the backup system fai led to operate as expected. As a result the plant did

not dose chlorine for a period of about six hours. Frankley works suppl ies

around 1.5 mil l ion people in Birmingham and parts of the West Midlands. A

crit ical treatment works supplying water to the UK’s second largest city,

the consequence of a loss of disinfect ion and possib ly the supply, at the

very least would cause signif icant disrupt ion to the consumers and the

city.

The company carr ied out an invest igation and determined the computer

control ler of the main chlorine dosing system had failed. The system was

such that this same control ler operated the back -up system and provided

information to the control centre. The event resulted f rom t he single

operat ional control dependency of both the primary and back -up

disinfect ion. Consequential ly when the control system failed, the works

failed and the company were unaware of the status of dosing. The

Inspectorate attended the site in October and issued a Provisional

Enforcement Order in relat ion to a failure to adhere to the condit ions of an

exist ing Not ice at the works. This is a very unusual step for the

Inspectorate to take and ref lects the ser ious concerns to the fundamental

principle of having separate systems on crit ical processes. The order

required the company to reassess the design and control of the works to

ensure that chlorinat ion systems did not fai l in this way. I t also st ipulated

that suff icient trained staff were avai lable to run th e plant, part icular ly

outside normal working hours. The company has redesigned the system

appropr iately complying with the Provisional Enforcement Order.

The Inspectorate reminds senior managers in the industry that they are

responsible for ensuring systems are in place and are robust to prevent

inadequately treated and disinfected water entering supply f rom works, a

point made repeatedly this year and over the 25 years it has been a

requirement. This pr inciple, arguably of resi l ience for companies, is not

solely about interconnectivity, but also retaining focus on the f irst

principles of operating treatment works which are too crit ical to fail.

Northe rn reg ion

59

Auto shut-down arrangements

As a precautionary measure to ensure water is appropr iately treated and

disinfected before leaving works, a safeguarding system was instal led to

prevent a works f rom being started when turbidity increases above the

standard of 1NTU. This was in response to an event at Matts Hi l l works in

2008 where the company was prosecuted in 2010 for p ermitt ing turbid

water to enter supply by repeatedly overriding fail safe controls. In July

2014 the Inspectorate received information concerning the abil i ty to evade

this new system by bypassing on-l ine monitors at works. Doing so would

permit a works to start improper ly where otherwise an alarm would sound

in response to the presence of turbidity or chlor ine problems safeguarding

untreated water entering suppl ies.

A series of 12 investigatory site audits were carr ied out to investigate this

information and following detai led test ing it was conf irmed that it was

possible to bypass on-l ine monitors without alarms being raised and avoid

sites being automatical ly shut down. Investigations noted the instrument

design permitted nominated operators to start certain sites without causing

a shutdown, however, the knowledge of the method had become commonly

known and subsequently used inappropr iately through the wider area of

the company. By allowing this pract ice to continue, local management and

therefore the company had fai led to put adequate measures in place to

prevent rout ine abuse of the very system designed to prevent

inappropr iate pract ice and consequent ly the potential increased r isk to its

customers.

The monitor alarm system has since been updated and the company

in it iated the need for managers’ intervent ion when sites sound an alarm

indicating water qual ity is outside the set parameters. Any attempted

bypassing of on-line monitors is now clearly visible on the company’s

SCADA system. Following the discovery by the Inspectorate, the company

has worked closely with the on- l ine monitors’ manufacturer, to determine if

the monitors could be bypassed in other ways and to ensure future

untoward tampering is prevented.

This serves to remind companies that when expensive on-l ine monitor ing

systems are ordered and installed, appropriate verif icat ion should be

carr ied out as part of the commissioning stage where al l relevant persons

within the company are involved , including process and water quality

scientists. I t is disappoint ing to state that whi le such occurrences are very

rare, the opportunity for an operator to defeat monitors in order to start -up

works must be considered a r isk and mit igated appropr iately . Simple r isk

mit igat ion methodology wil l also remove the impossible posit ion some

operators are put in where no facil i ty exists to deal with a qual ity problem

due to an inappropriate design of the works. Such mit igat ion may be as


60

simple as a run to waste facil i t y at treatment works, where qual ity issues

are of ten seen dur ing init iat ion of a works or sett ing water qual ity tr iggers

appropr iately for each site.

Turbidity event due to lime dosing failure – single point of failure

In October, it was reported that water with elevated turbidity had been

leaving Legacy works, which suppl ies approximately 44,000 consumers in

Legacy and Rhos zones. This surface water works uses l ime dosing for pH

correct ion to opt imise the coagulat ion process af ter which it passes

through rapid gravity f i l ters and then onto chlor ination wh ere l ime is added

once again to ensure a suitable pH for dis infect ion. The ef fect iveness of

chlorine used for disinfect ion is part ly based around the pH of the water it

is dosed into and at Legacy work is measured by a single probe which also

controls the l ime dosing adjustment.

In the week leading up to the event, the company exper ienced problems

with the pre-contact pH probe, in the form of drif t , when compared to

manual pH readings. The probe was cleaned, recal ibrated and returned to

service. However, the probe began to drif t again. The drif t caused false

pre-contact pH readings and the l ime dosing system increased dosing as it

tr ied to compensate. As the same probe control led the dosing and

monitor ing, no alarms were tr iggered and the site did not auto s hutdown.

While the result ing increase in pH was recorded by the f inal water pH

monitor, at the t ime this was not l inked to alarms or the automatic

shutdown system. The event eventual ly manifested as high f inal water

turbidity f rom the excess l ime. At that t ime, the site auto shutdown alarms

were set to respond to f i l tered turbidity, pre -contact chlorine and pre-

contact pH. As none of these alarms were tr iggered, water with turbidity

>1NTU was presented for disinfect ion and entered supply for a period of

approximately 15 hours with the pH r is ing to 9.3.

The company instal led a second pre -contact pH probe, so that monitor ing

and l ime dosing control are handled separately. This wi l l prevent a repeat

of this event, as a single probe defect cannot cause complete failure of the

pH control and monitoring. Addit ional ly, monitors not previously l inked to

alarms, including the f inal water pH probe are now alarmed, al lowing

greater control of the works.

This event i l lustrates both the failure to prevent inadequately treated and

disinfected water entering supply f rom works and the failure to adequately

identify the r isk of not having separate systems which control inter l inked

crit ical processes consequent ly leaving the works without a robust cr it ical

measure, and subsequently and unknowingly losing control of the works. I t

is questionable how such a basic element of r isk control was missed and

why companies must ensure a site set up is fully known and is appropr iate

Northe rn reg ion

61

for its operation at al l t imes. The not so obvious r isk i n al l of this is the

effect of a raised pH, some two points over normal. How aggressive the

now highly alkaline water has become may not be truly known, but the r isk

of metals from the network should be considered as company directors are

reminded that they are responsible for supplying water which must not be

aggressive.

Chapter 6: Technical audit activity

Chapter 6:

Descr ibes the audit strategy of the Inspectorate.

Summarises the outcome of audit act ivity in 2015.

Highlights learning points for the industry.

Summarises the strategic AMP6 dr inking water improvement

programme.

The Inspectorate has operated a r isk -based approach to technical audit

since 2005 and no technical audit takes place without a reason.

Technical audit is the means by which the Inspectorate ver if ies whether

companies are operating and maintaining water suppl ies in a sustainable

manner that is l ikely to secure a safe , clean supply of drinking water into

the future. Audit act ivit ies take a number of dif ferent forms:

Assessment of information provided by water companies.

On-site inspection of company records, procedures and plans.

Meet ings to chal lenge the veracity of specif ic plans, procedures or

programmes of work.

For the purposes of the report the audit act ivit ies in 2015 are divided into

two tables. Table 22 summarises the outcomes of inspect ions , including

consumer complaint investigations. Table 23 covers the outcomes of audits

relat ing to the enforcing of water qual ity improvements.


62

Table 22: Outcomes from inspections and consumer complaint

investigations in 2015

Company Location and Reason

Main f indings from audit

Audit focus: Abstract ion and treatment

Hart lepool Dal ton Piercy works and downstream

Throston service reservoir fol lowing turb id i ty event at works

Sat isfac tory

Recent ly insta l led work at Dal ton Piercy works inc luding new UV dis infect ion stream, booster s tat ion, upgraded sampl ing points and greater power res i l ience and secur ity g ives s i te greater res i l ience and protect ion.

Uni ted Ut i l i t ies Frank law works, Barnacre works and Broughton works, Barnacre reservoir , Haighton reservoir , Houghton reservoir , Warbreck reservoir and Tower , Pike Lowe reservoir , Whitebu l l reservoir , Weeton reservoir , W estby reservoir

Audi ted as par t of ongoing invest igat ions.

Uni ted Ut i l i t ies Hodder works –

d is infect ion

Unsat isfac tory

Concerns that s i te-specif ic d is infect ion Pol icy is inadequate for cer ta inty of d is infect ion.

Out of ca l ibrat ion f low moni tors and other indiv idual moni tors, recommended the company revise procedure for cal ibrat ion.

Due to s ite locat ion, poor response t ime to cr i t ica l a larms out of hours . This gave a lack of conf idence that there were suf f ic ient ly robust a larms and response procedures to prevent a reoccurrence of a d is infect ion fai lure.

Enforcement act ion is being progressed, in assoc iat ion wi th e ight other improper ly d is infected water events, to ensure robust systems, inc luding: process contro l ; pol icy and procedures; and asset improvement .

Northe rn reg ion

63



United Ut i l i t ies Lovec lough works – high pH events

Unsat isfac tory

Site-spec if ic d is infect ion pol icy –inappropr iate Ct calculat ion and no shut down cr i ter ia for turb id ity enter ing contact tank.

Inadequate informat ion was avai lable to assess the competency of s i te and operat ions s taf f .

The push pul l nature of the con tact tank means that d istr ibuted water can get back into the f inal water tank.

A Not ice issued based on Reg 26 r isk of supplying water as a danger to health.

Uni ted Ut i l i t ies Sweet loves works fo l lowing d is infect ion events

Unsat isfac tory

Poor contro l by company of cr i t ica l contro l points and a larm set t ings and pr ior i t ies required.

Inadequate feedback of a larms for contro l of ch lor ine dos ing.

Cr i t ic ism by the Inspectorate of company-wide d is infect ion pol ic ies. Pol ic ies and operat ing procedures should be s it e-spec if ic .

Not ice issued.

Yorkshire W ater Rivel in works – process audit and Regulat ion 28 review

General ly sat isfac tory

Concern regarding >10 per cent return of wash-water to head of works when s i te is on reduced f low.

Sample label l ing unc lear wi th redun dant sample points in v ic in i ty of statutory points .

Suggest improved awareness for a l l s taf f of any changes to procedures.

Audit focus: Service reservoirs integrity and management

Uni ted Ut i l i t ies Malpas tanks 1+2

Cotebrook tanks 1+2

Nor ton tank – break tank audits

Unsat isfac tory

No regular sampl ing at these assets and they f i t the cr i ter ia for def in i t ion of service reservoir .

Company to update asset def in it ion to include as service reservoirs .

Discussed outcome of break tank audits by br ief to W aterUK.

Yorkshire W ater West End tank

Healey tank – break tank audits

Unsat isfac tory

No regular sampl ing at these assets and they f i t the cr i ter ia for def in i t ion of service reservoir .

Company to update asset def in it ion to include as service reservoirs .

Discussed outcome of break tank audits by br ief to W aterUK.


64



Audit focus: Consumer complaint handling

Uni ted Ut i l i t ies Other (1)

Taste and odour (3)

4 Sat isfac tory

Yorkshire W ater Discolourat ion (2)

Taste and odour (1)

3 Sat isfac tory

During 2015, the Inspectora te focused on two special areas within its audit

programme. Focusing on special areas is addit ional to the r isk -based

programme described above and is usual ly where sites or assets are

outside the requirement for companies to submit data under regulatory

monitor ing, but have the potent ial to affect water qual ity. These areas

were for structures cal led break tanks and for bulk transfer of water.

Break tanks exist in networks for operational reasons of ten to al low a

change of pressure from one area to the ne xt or as a safeguard against

backf low and are usual ly relat ively small . These are not considered to be

regulatory assets unl ike a service reservoir which are considered to be a

stored reserve of water to meet a var iable demand and can be a range of

sizes sometimes containing mil l ions of l i t res of water.

These tanks represent a similar r isk in companies’ distr ibut ion systems as

service reservoirs and can provide an access route for external

contamination to enter the water supply i f not maintained. Unl ike s ervice

reservoirs, monitoring is not specif ied in the Regulat ions and is lef t for the

company to determine along with the r isk assessment. The Inspectorate

has been not if ied of at least two events that included a microbiological

failure associated with a break tank and considered it appropriate to

establish their number and signif icance for drinking water qual ity.

Companies, when asked as part of the audit , declared 55 break tanks from

which the Inspectorate then carr ied out 13 site audits. The audits looke d at

a number of aspects to develop an understanding of the tanks in use and

this included; age, construct ion, capacity and the t ime water was retained

as wel l as qual ity considerat ions such as sampling, maintenance,

inspect ions and if they were within the company’s r isk assessment.

Even though the Regulat ions do not specify the monitor ing requirements of

break tanks, we would expect companies to treat them similar to service

reservoirs as they present a similar r isk to the water supply. The

Inspectorate concluded that this was not the case. In tanks, which ranged

from 6 to 130 years, some were in very poor condit ion. While most

companies undertook weekly vis its to tanks for maintenance checks, the

internal inspect ion f requency was between 1 – 15 years and some were

Northe rn reg ion

65

never inspected. The question ar ises therefore; what were the companies

doing to assure themselves there were no developing qual ity problems? In

39 (71%) cases, there was no sampling at all and in 13 (24%) cases the

companies had not even included the tank in their r isk assessment. Senior

managers of water companies are reminded that they are responsible for

complet ing r isk assessments for the whole supply system and not to do so

wi l l result in enforcement act ion.

Turning to the tanks themselves: The capacit ies of the tanks audited

var ied between 359l up to 19.35Ml , the largest being about eight t imes the

size of an Olympic swimming pool and the longest retent ion t ime, of those

which were known, was found to be over three days. Several sites were

found to have been previously designated as service reservoirs and were

reclassif ied as break tanks. Senior managers must ask themselves, why in

some cases these are not a stored reserve of water to meet a var iable

demand and why some were reclassif ied as tanks, effect ively increasing

the r isk. Two companies have proact ively stated they wi l l reclassify their

break tanks as service reservoirs and commence regulatory sampling and

report ing. This has been taken into account in the forward plan for the

Inspectorate and sites which were identi f ied as a r isk, or incorrect ly

classif ied, wi l l be the subject of further audits.

The second special area of interest in 2015 was water companies’

arrangements for bulk transfers. The water industry has many

interconnections within and between water companies that al low the

interchange of water to ensure a suf f icient volume is avai lable. These

suppl ies are referred to as bulk transfers or bulk suppl ies. When a

company suppl ies water to another company both are responsible in th is

arrangement. That means water must be wholesome when exported and

must not cause a deteriorat ion to the system at a later point by the effects

of the change in the source. Equal ly, the importer must ensure they have

taken measures to secure suitable water for their system. This is achieved

through information sharing and a combined r isk assessment ahead of any

transfer.

In North London during 2012 an export of water f rom one company to

another resulted in a taste and odour event, this was reported in Drinking

water 2012 . In response, companies undertook to share qual i ty information

and up-to-date knowledge of the status of al l bulk transfers ( including both

inter-company and intra-company transfers). However, dur ing 2013, two

events were not if ied to the Inspectorate where a bulk transfer connect ion

was in place, but the companies involved did not know if i t was in

operat ion or which consumers were served by it .

In 2015, the Inspectorate ident if ied further evidence that weaknesses

existed in the protocols and arrangements for bulk suppl ies. The


66

Inspectorate inst igated an audit to establ ish the current status of

arrangements for bulk transfers and their f i tness for purpose, the

strategies for operating bulk transfers, communicat ion with receiving

companies, and sharing of water qual ity data. In total, 24 companies were

audited and one was selected for a site audit to assist with a more detai led

inspect ion of communications between supplying and recipient water

companies.

As a forward strategy for companies to develop their resource and

resi l ience plan involving bulk transfers, it would be expected that senior

managers would, by 2015, have clear f ramework agreements and r isk

assessments to ensure water qual ity is the highest pr ior ity. The

Inspectorate was there fore disappointed to identify 25% of the companies’

bulk transfer protocols did not include a regular transfer of data or

interact ion between provider and recipient company , nor had the majority

of arrangements audited been reviewed or updated since being introduced

in 2012. Companies failed to share r isk assessments, water qual ity data or

any other water qual ity r isk mit igat ion approach for supplies between

companies or within companies. Companies should ensure that they are

fully aware of the r isks when export ing or import ing water and they have

taken all steps to assess the r isk to both companies.

The Inspectorate as part of its better regulat ion strategy, shared with the

industry the f indings from these audits in November 2015 at WaterUK. As

best pract ice, the advice to companies has been incorporated into the

revised guidance of the Regulat ions, currently in consultat ion and

scheduled for release in early summer 2016.

Table 23 summarises the Inspectorate’s act ivity in relat ion to

improvements to water quality. These act ivit ies cover the putt ing in place

of Notices or undertakings and the checks made to ensure the work

specif ied by the company is technical ly appropr iate, has been carr ied out

in the required t imescales and the benef its to water qual ity have been

real ised.

Northe rn reg ion

67

Table 23: Outcome of audit activities relating to enforcing water

quality improvements

Activity Number of improvement programmes (and outcomes)

Issuing of statutory instruments

Not ices:

DVW (2) , HPL (1) , YKS (1) , UUT (14)

Reviewing schemes

Schemes reviewed: DVW (14) , NNE (5), YKS (22) , UUT (38)

Changes of solut ion

Schemes examined:

DVW (1), UUT (1) , YKS (1)

Closure of schemes

Schemes reviewed for c losure: Sat isfac tory – scheme closed

DVW (15), UUT (11), YKS (3) ,

Inspect ion of schemes

None dur ing per iod

Receipt of r isk assessments*

DVW (19,917), HPL (1 ,859), NNE (101,444), UUT (64 ,839), YKS (15,283)

*These f igures represent l ines of data reported to the Inspectorate . The outcome of the review of the data can be found in the Inspectorate ’s new quarter l y report

2.

For further information on the Water Supply (Water Qual ity) Regulat ions

2000, or the microbiological and chemical parameters covered by the

regulat ions please refer to the DWI website (www.dwi.defra.gov.uk) .

I f you have a need for more specif ic information than that on our website,

please contact us on the DWI enquiry l ine: 0300 068 6400.

2 h t tp: / /dwi .defra.gov.uk/about/annual -report /2016/ index.html


68

Annex 1 Further sources of information

The reports and other content are publ ished on the DWI website only

(www.dwi.defra.gov.uk).

The publ icat ion Drinking water 2015 comprises the regional reports for

England and a report covering Wales. There are four regional reports for

England (Central and Eastern, London and South East, Northern, and

Western) and one for Wales ( in two languages). Each report presents

information f rom 2015 under the following headings:

Summary.

Water supply arrangements.

Drinking water qual ity test ing.

Drinking water qual ity results.

Drinking water qual ity events.

Technical audit act iv ity.

There are also separate reports covering private water supplies, one

cover ing England and one covering Wales ( in two languages).

Water company look-up tables

These summarise al l the results of water company monitor ing in 2015.

They provide information on:

what was tested;

how many tests were performed;

the range of the results of test ing; and

how many tests failed to meet the standards.

Significant drinking water quality events in England and

Wales 2015

To promote shared learning, the Inspectorate has compiled a l ist of al l

signif icant, serious and major events that occurred in 201 5, which

i l lustrates the nature and cause of each event, the main act ions by the

company and f indings f rom the inspectors’ assessments. Relevant content

f rom this overal l l ist is contained in an annex to each regional report.

Northe rn reg ion

69

Annex 2 Information relating to public water supplies published by the Inspectorate in 2015

Information Letters

Ref Title

01/2015 Regulat ion 28 report ing requirements

02/2015 Legal Instruments – Processes for report ing on, agreeing

changes to and closure/revocat ion

03/2015 Regulat ion 31 approval of products and substances intended for

dis infestat ion, disinfect ion or cleaning agents of waterworks

apparatus and distr ibut ion systems

04/2015 Publ icat ion of a research report on the signif icance of chromium

in dr inking water

05/2015 Publ icat ion of research: Understanding the impl icat ions of the

European requirements relat ing to radon in dr inking water

The le t te rs , and the i r assoc ia ted annexes , can be found on the Inspec tora te ’s webs i te a t ht tp : / / www. dwi . def ra .gov.uk /s takeholde rs / in fo rmat ion - le t te rs / index.h tm

Technical guidance

World Health Organisation technical br ief – Boi l water

Copies o f the above gu idance can be found on the Inspec tora te ’s webs i te a t ht tp : / / www. dwi . def ra .gov.uk /s takeholde rs /gu idance -and-codes -o f -prac t ice /


70

Research

Ref Title

DWI 70/2/223 Free-Living protozoa and opportunist ic pathogens in

distr ibuted water

DWI 70/2/256 Risk assessment of VTEC infect ions in English and Welsh

drinking water

DWI 70/2/261 Effect ive microbial control strategies for main breaks and

depressurizat ion

DWI 70/2/275 Understanding the signif icance of chromium in dr inking

water

DWI 70/2/281 National assessment of the r isks to water supplies posed

by low taste and odour threshold compounds

DWI 70/2/292 Volat i le organic compounds – Understanding the r isks to

drinking water

DWI 70/2/300 Effect of UV on the chemical composit ion of water

including dis infect ion byproduct formation

DWI 70/2/301 Understanding the impl icat ion of the EC’s proposals

relat ing to radon in drinking water for the UK

Copies o f res earch repo r ts and exec ut ive summar ies can be found on the Inspec tora te ’s webs i t e

at h t tp : / / www.dwi .def ra .gov.uk / res earc h/comple ted

Northe rn reg ion

71

Annex 3

Not significant and minor drinking water quality events Nature Number of not signif icant and minor events Area a ffected (est imate of populat ion affected)

Chemical

UUT (2) Knuts ford, Cheshi re (5) L iverpool (3)

YKS (1) Thur ls tone, South Yorkshi re (3)

Discolourat ion

HPL (1 ) Har t lepool (425)

UUT (1) Blackburn, Lancaster (24,152)

YKS (1) Leeds (3)

Heal th concern

NNE (1) Ot terburn, Northumber land (947)

YKS (1) Bradford , W est Yorkshi re (3)

Inadequate t rea tment

NNE (1) Wooler , Northumber land (4,882)

UUT (2) But termere , Cumbr ia (27) Cockermouth, Cumbr ia (63,007)

Loss of suppl ies / poor pressure

DVW (1) Wrexham and surrounding areas (15,000)

HPL (2 ) Hart lepool (910) Hart lepool (3)

UUT (3) Areas of Lancaste r and Morecambe, Lancashi re (220) Langwathby, Cumbr ia (500) Pat terda le and Glenr idd ing, Cumbr ia (645)

YKS (1) Pock l ington , Yorkshi re (12,500)

Microbio log ica l

HPL (1 ) Hart lepool (3)

YKS (1) Sk ipton, North Yorkshi re (1 ,700)

Other

HPL (2 ) Hart lepool (3) Hart lepool (1)

UUT (1) Severe f looding, Nor th Lancashi re (N/A)


72

Nature Number of not signif icant and minor events Area a ffected (est imate of populat ion affected)

Publ ic concern

DVW (1) Hol t and sur rounding a reas, F l in tsh i re (9 ,578)


NNE (3) Gateshead, Tyne and Wear (1) Great Ayton, North Yorkshi re (3) Wal lsend, Tyne and W ear (3)

UUT (3) Aughton, Lancashi re (3) Malpas, Cheshi re (3) Mi l lom, Cumbr ia (3 )

YKS (5) Bever ley and Hul l , nor th Yorkshi re (3) Harrogate, North Yorksh i re (5) Marsden, W est Yorkshi re (3) Twi t ter message (N/A) Yeadon, W est Yorkshi re (3)

Taste o r odour


NNE (1) Peter lee, Durham (3)

UUT (5) Audlem, Cheshi re (3) Manchester (3) Nantwich, Cheshi re (3) Preston, Lancashi re (3) Thurs tonf ie ld , Cumbr ia (3)

YKS (1) Swinton, South Yorkshi re (3)

Total 44 – DVW (2) , HPL (8 ) , NNE (6) , UUT (17) , YKS (11)

134,575

Northe rn reg ion

73

Significant, serious and major drinking water quality events

Date and durat ion

Area Estimate of populat ion affected

Nature and cause of the event

Main act ions and f indings from the Inspectorate investigat ion

11 Jan 2015 For 1.5 hours (UUT)

Poaka Beck works, Barrow and Cumbr ia

100,043 Improper ly d is in fected wate r due to fa i lure of pH contro l equipment .

United Uti l i t ies Water Plc act ion:

Shut down t reatment works.

Repai red pH contro l equ ipment .

Ins ta l led new chlo r ine analysers .

Ins ta l led addi t ional p rocess a larms for automated t reatment contro ls .

DWI comments and f indings:

Lack of maintenance of cr i t ica l pH cont ro l equipment led to improper ly d is in fected water leaving the works . The company fa i led to adequate ly assess the r isk of such fa i lures and a lso fa i led to ensure that robust respons e and recovery p lans were in p lace. A number o f recommendat ions were made that the company should take s teps to address the root causes of th is and s imi lar events , inc lud ing :

Review r isk assessments and mi t igat ion for def ic ienc ies in chemical dos ing system s and t rea tment systems that a re not operat ing correct l y.

Develop ef fect i ve cont ingenc ies and safeguards to preven t compromised water t reatment .

Respond and rect i fy issues expedient l y.

Inc lude immediate downstream assets in the company’s response to t reatm ent and d is in fect ion fa i lure events .

Risk c lass i f icat ion: Sign i f icant


74

Date and durat ion




16 Jan 2015 For 5 hours (UUT)

Oswestry works, Shropshi re

100,000 Chlor inat ion fa i lure at the works due to p lant fa i lure.


No act ions taken.

Review of procedures.


The company fa i led in the i r duty to not i fy th is event which was ident i f ied by the Inspectorate fo l lowing a compl iance fa i lure.

The company fa i led to adequate ly moni tor , mainta in or ident i fy fa i lures in the d is in fect ion process.

Enforcement act ion is be ing progressed, in assoc iat ion wi th e ight o ther improper ly d is in fected water events , to ensure robust systems, inc lud ing: process contro l ; po l icy and procedures; and asset improvement .

Invest igat ion ongoing. Risk c lass i f icat ion: Sign i f icant

17 Jan 2015 For 3 days (YKS)

North Leeds 700,000 Brown d isco lourat ion fo l lowing p lanned work .

Yorkshire Water Services Ltd act ion:

Sampled af fected a rea.

Rezoned area (brought in water f rom d i f fe rent source) .

F lushing cons idered but not thought to be ef fect i ve . DWI comments and f indings:

The even t was caused by d is turbance of depos i ts fo l lowing a bypass main being le f t open a f ter work on an upstream service reservo i r .

The company:

fa i led to carry ou t a robust r isk ass essment pr ior to undertak ing th is p lanned work.

was requi red to amend i t s procedures to ensure that r isk assessments for water supply zones are updated af ter changes to the network.


Northe rn reg ion

75

Date and durat ion




17 Jan 2015 For 3 days (YKS)

Keighley, Yorkshi re

23 Do not d r ink not ice due to company contractors damaging a wate r main whi le repai r ing a burs t sewer.


Repai red main.

F lushed and d is in fected the main.

Issued a do not dr ink no t ice to e ight commerc ia l propert ies .

Provided bot t led wate r on request .

Increased ch lor ine leve ls in the d is t r ibut ion system.

The company b r ie fed a l l service par tner teams to a ler t them to the r isks assoc iated wi th the cause of th is event .

Assoc iated procedures were reviewed. DWI comments and f indings:

The company invest igat ion, response, provis ion of in format ion and ass is tance was sat is factory.


21 Jan 2015 For 12 hours (UUT)

Whi tehaven 4,000 Brown d isco lourat ion fo l lowing p lanned work to recommiss ion a repai red main .



F lushed mains. DWI comments and f indings:

The Inspectorate was cr i t ica l o f the company’s response to commence invest igat ional sampl ing.

Insuf f ic ient supervis ion of contract ors who were operat ing va lves.

The company’s records of water mains in the a rea were inaccurate and fur ther va lv ing work by the company exacerbated the problem.

Evidence was obta ined f rom consumers which demonstrated that consumers had re jected the water o n aesthet ic grounds .



76

Date and durat ion




28 Jan 2015 For 24 hours (HPL)

Owton Manor, Hart lepool

3 ,750 Brown d isco lourat ion caused by f low changes as a resul t o f a leak ing main which led to d is turbance of depos i ts .

Hart lepool Water P lc act ion:

Repai red main.


Sampled af fected a rea. DWI comments and f indings:

The company’s response to th is event was sat is factory and no fur ther act ion wi l l be taken.


05 Feb 2015 For 12 hours (NNE)

Darras Hal l , nr Newcast le , Northumber land

7,248 Brown d isco lourat ion due to burs t main .

Northumbrian Water Ltd act ion:

Repai red main.

F lushed mains.


The company’s response to th is event was sa t is factory and no fur ther act ion wi l l be taken.


06 Feb 2015 For 3 days (UUT)

Skelmersdale 27,875 Brown d isco lourat ion due to burs t main .



Repai red main.


A large d iameter main was damaged by con tractors dur ing a repai r operat ion. The company caused fur ther d isco lourat ion when a pumping s tat ion was swi tched on.

There was no evidence that the company carr ied out a r isk assessment for the in i t ia l mains repai r .

The r isk assessment d id not take in to account r i sks assoc iated wi th opera t ion of the pumping s ta t ion .

Recommended that r isk assessments are carr ied out by the company p r ior to work be ing undertaken on the d is t r ibut ion system and to inc lude a l l c r i t ica l operat ions.


Northe rn reg ion

77

Date and durat ion




07 Feb 2015 For 5 hours (HPL)

Hart lepool 13,578 Brown d isco lourat ion due to burs t main .

Hart lepool Water Plc act ion:

Repai red main.


F lushed mains.


Retra ined s ta f f on sampl ing arrangements .

Dedicated bot t le sets now set as ide fo r any fu tu re events . DWI comments and f indings:

Sample bot t les avai lab le for the event were inappropr ia te for the requi red analys is .


09 Feb 2015 For 1 hour (UUT)

Appleby, Cumbr ia

65 Discoloured water in school due to loca l ised d is turbance of depos i ts .


The company iden t i f ied the unauthor ised use of a hydrant by a c leaning contractor and updated i ts assoc ia ted procedures.

Do not d r ink advice issued to a school .

The company car r ied out a water f i t t ings inspect ion in the school and requi red i t to correct f i t t ings which d id not meet the necessary s tandards.





78

Date and durat ion




07 Mar 2015 For 5 days (HPL)

Dal ton Pie rcy works, W ynyard

1 ,115 Loss of suppl ies and d isco lourat ion fo l lowing p lanned work.


F lushed mains.


Repai red fau l ty equipment .


The company restored suppl ies qu ick ly and acted d i l igent ly.

The company has improved t imely de l i very o f analyt ica l resu l ts .


Inadequate sampl ing and invest igat ion, which fu r ther emphasised inadequacies seen previous ly dur ing the event in Har t lepool on 7 February 2015 and s imi lar occurrences at Throston works in 2014.

The company has p rovided assu rances to improve i ts procedures and approach to invest igat ing events . A fur ther s imi lar even t is l i ke ly to resul t in enfo rcement .


25 Mar 2015 For 1 day (YKS)

Kingston on Hul l

365,000 Loss of suppl ies /poor pressure due to loss of te lecommunicat ions to pumps.




The company quick ly ident i f ied the issue and res tored suppl ies .


The company’s response to th is event w as sat is factory and no fur ther DW I act ion wi l l be taken.


Northe rn reg ion

79

Date and durat ion




30 Mar 2015 For 13 hours (UUT)

El lesmere Por t 29,292 Brown d isco lourat ion due to p lanned work .


F lushed mains.

Review o f procedures.

In t roduced new r isk assessment process.


An Undertak ing is in p lace to c lean the large d iameter mains wi th in the a rea.

The company were c r i t ic ised for an inadequate r i sk assessment , which d id not take account o f f l u sh ing and a l ternat i ve supply opera t ions whi l e mains recharge was being conducted, resul t ing in d isco loured suppl ies .

Inadequate procedures.

Invest igat ion ongoing.


31 Mar 2015 For 12 hours (UUT)

Sweet loves works, Bol ton, Greate r Manchester

180,291 Improper ly d is in fected wate r due to fa i lure of pH contro l .


B lended supply wi th ano ther source.


Reviewed a la rm response procedures and made improvements to t reatment contro l systems, in par t icu lar contro l o f pH.


An audi t o f the works was carr ied out . Key f ind ings inc luded:

Fa i lure to mainta in equipment .

Inadequate d is in fect ion t reatment process.

Inadequate procedures.

Enforcement act ion is be ing p rogressed, in assoc iat ion wi th e ight o ther improper ly d is in fected water events , to ensure robust systems, inc lud ing: process contro l ; po l icy and procedures; and asset improvement .

The Inspectorate is addi t ional ly cons ider ing the of fence of fa i l ing to adequate ly t reat or d is in fect water .



80

Date and durat ion




01 Apr 2015 For 24 hours (YKS)

Br ind, East Yorkshi re

10 Do not d r ink not ice due to poss ib le contaminat ion fo l lowing damage to a water main by a th i rd par ty .

Yorkshi re Water Services Ltd act ion:

F lushed mains.

Increased ch lor ine res iduals in the d is t r ibut ion system.

Issued a do not dr ink no t ice to f i ve propert ies in Br ind, Wress le, near Howden.

Repai red main.


The company’s response to th is event was sat is factory and no fur ther DW I act ion wi l l be taken.


10 Apr 2015 For 20 hours (UUT)

Stockton Heath, Warr ington, Cheshi re

30,196 Brown d isco lourat ion due to mains damage by th i rd par ty.


F lushed mains.

Repai red main.


Contracto rs damaged an a i r va lve whi l e con travening company pol icy. The a i r va lve was not on company records .

The con tractor fa i led to have adequate procedures for excavat ion and fa i led to observe the requi rement not to use mechanica l excavat ion in an area where i t was prohib i ted to p rotect f rag i le mains.

The company fa i led to adequate ly supervise the act iv i t ies of the i r cont ractors on s i te .

The company fa i led to learn f rom previous even ts and subsequent in tervent ion in the network to iso la te and la ter re turn the main resul ted in d isco lourat ion.


Northe rn reg ion

81

Date and durat ion




10 Apr 2015 For 3 weeks (UUT)

Wrenbury, Nantwich, Cheshi re

15 Boi l wate r not ice issued fo l lowing the d iscovery a th i rd par ty had damaged and repai red a main wi thout p roper author isat ion.


Repai red main.

Issued a boi l wate r not ice.

Sampled the af fected area . DWI comments and f in dings:

The company’s response to th is event was sat is factory and no fur ther act ion wi l l be taken .


13 Apr 2015 For 4 days (UUT)

Hazel Grove, Stockport



Repai red main.



Provided an a l te rnat i ve supply by tanker /bowser .

F lushed mains.

In i t ia ted an engineer ing review of the i r t runk mains .

Updated the r isk assessment for t he supply zone . DWI comments and f indings:

Recommended to not i f y events in a t imely manner.

Invest igat ion and sampl ing were inadequate , inc lud ing fa i lure to iden t i f y subsequent r isks at a publ ic bu i ld ing.

Requi red the company to report on the engineer ing review and any assoc iated r isk and mi t igat ion .



82

Date and durat ion




15 Apr 2015 For 1 hour (YKS)

Rive l in works, Shef f ie ld , South Yorkshi re

236,000 Microbio log ica l contaminat ion (C.per f r ingens ) .

Yorkshire Water Services Ltd act i on:

Sampled the af fected area.

Invest igated t reatment p rocesses.

Repai red potent ia l po ints of ingress in the f ina l water tank.

Made changes to the on-s i te f low cont ro l system.

Clostr id ium per f r ingens was detected in a rout ine sample.

Extens ive invest iga t ions by the company fa i led to establ ish the root cause.




16 Apr 2015 For 4 days (UUT)

Cockermouth 107,500 Brown d isco lourat ion due to th i rd par ty main damage and deplet ion of t reated water tank at Cornhow works .



Repai red fau l ty turb id i ty moni tor .

Repai red main.

Conducted s taf f br ie f ing of a new r i sk assessment procedure.

Cleaned and inspected the service reservo i r a f fec ted dur ing the event .

Implemented enhanced moni tor ing at the works. DWI comments and f indings:

Inadequate r isk assessment , lack of maintenance of equipment and a poor response to the event . The company invest igat ion and sampl ing contr ibuted to the sever i t y and durat ion of th is event .

Recommended that on l ine ins t ruments at works should be regular l y checked in order to ensure that the ef fect iveness of operat ion and d is in fect ion at a l l t imes and appropr ia te invest igat ional sampl ing is undertaken in re sponse to events .


Northe rn reg ion

83

Date and durat ion




17 Apr 2015 For 4 days (NNE)

Byker , Heaton, Wal lsend and Walker areas of Newcast le

100,000 Loss of suppl ies and brown d isco lourat ion due to p lanned work on a large d iameter main .


Replaced fau l ty equipment .

F lushed mains.


Rezoned area (brought in water f rom d i f fe rent source) . DWI comments and f indings:

Cr i t ica l equipment used by contrac tors fa i led dur ing c leaning and subsequent network changes in response led to the d isco lourat ion of suppl ies .

The even t was exacerba ted by shortcomings in competency, communica t ion and delays in response.

The company were reminded of the i r duty to p rovide a l l in format ion in a t imely manner under the Act as th is cannot be defer red by any legal act ion in tended by the company against i ts ’ con tractors .

Recommended that the company reviews the competency of i ts contractors and the in tegr i t y o f apparatus used dur ing the iso la t ion of mains.



Bai ldon, W est Yorkshi re



Repai red main.

F lushed mains.


Resamples were sat is factory. DWI comments and f indings:

The company’s response to th is event was sat is factory and no fur ther act ion wi l l be taken .



84

Date and durat ion




23 Apr 2015 For 1 day (YKS)

Beauchief and Tot ley a rea of Shef f ie ld , South Yorkshi re

14,118 Brown d isco lourat ion due to p lanned work .


F lushed mains.



Retra ined s ta f f .

Undertook model l ing s tud ies to ident i f y reasons for the increase in f low.

Used th is event as a development too l for i ts operat ional s ta f f .

Updated the r isk assessment process to ensure greater scope dur ing p lanned work .


Inadequate r isk assessment pr ior to the p lanned work be ing carr ied out resul t ing i n fa i lure to adequate ly not i f y consumers of l ike ly d isco lourat ion .



Skelmenthorpe, West Yorks

4,110 Brown d isco lourat ion fo l lowing p lanned work on Skelmenthorpe service reservo i r .



Bypassed service reservo i r .


F lushed mains . DWI comments and f indings:

The company fa i led to adequate ly r isk assess p lanned work.

The even t was exacerba ted through poor communicat ion and mis in format ion of the work in hand and subsequent ly poor invest igat ional response, sampl ing and l ia ison wi th loca l heal th profess ionals .

Recommend the company to review va lve operat ion procedures, invest igato ry cr i te r ia for sampl ing in response to even ts , and procedures for not i f y ing loca l author i t ies and Publ ic Heal th England.


Northe rn reg ion

85

Date and durat ion




07 May 2015 For 46 days (UUT)

Kears ley, Bol ton

150 Chemical contaminat ion: Copper leve ls in the supply at a publ ic house.

United Uti l i t ies Wate r Plc act ion:

Issued a do not dr ink no t ice.


Inspected the pr i vate p lumbing system in the publ ic house and worked wi th the owner to resolve p lumbing defects .


Fo l lowing a consumer compla in t , the company foun d dangerous ly h igh leve ls of copper in the tap water in the pr ivate domest ic system of a publ ic house.

The company were c r i t ic ised for :

the t ime taken to ident i f y the root cause of the contaminat ion;

i ts fa i lure to carry out an urgent f i t t ings inspect ion;

fa i lure to serve a legal Not ice to ensure prompt rect i f icat ion of the p lumbing defects ident i f ied.

Recommendat ions were made that the company should improve i ts invest iga t ional sampl ing and analys is for events of th is nature where dr ink ing water is made avai lab le to members of the publ ic .


19 May 2015 For 1 week (UUT)

L ightshaw works, near Warr ington, Cheshi re

115,606 Chemical contaminat ion: Bromate exceedances due to t reatment fa i l ings .





Detect ion of b romate in f ina l wate r due to inadequate mi t igat ion of known r isks ident i f ied through company commiss ioned research.

Problem compounded by a ser ies of avoidable issues inc lud ing:

Poor contro l o f UV system;

Poor process cont ro l o f a source;

Fa i lure of key equipment ;

Poor contro l o f ch lor inat ion. Risk c lass i f icat ion: Sign i f icant


86

Date and durat ion




03 Jun 2015 For 78 days (UUT)

Al t r incham 13 Taste and odour due to ground contaminat ion fo l lowing a fue l sp i l lage.


Issued a do not use not i ce to a farm and industr ia l un i ts . Suppl ied bot t led wate r .

Protected the publ ic supply.

Replaced the service p ipe to the premises. DWI comments and f indings:

The company’s response to th is event was sat is factory and no fur ther DW I act ion wi l l be taken .


06 Jun 2015 For 1 day (UUT)

Oldham 64,829 Loss of supply and brown d isco lourat ion due to p lanned reservo i r dra in down.


Restored supply.


Modi f icat ion was made to ra ise the reservo i r out le t p ipework. Recommended to update records appropr ia te ly.

Suppl ied unwholesome water in breach of regulat ions, enforcement cons idered.

Recommended to review consumer advice regard ing safety of d isco loured suppl ies .


Northe rn reg ion

87

Date and durat ion




28 Jun 2015 For 1 hour (NNE)

Fontburn works, Northumber land

122,000 High turb id i ty on in le t to contact tank fo l lowing f i l te r washing compromis ing the d is in fect ion process .


Sampled works and af fected area.

Retra ined s ta f f . DWI comments and f indings:

Loss of contro l o f the t reatment f low through the process af fect ing mul t ip le t reatment s tages inc lud ing d is in fect ion.

Turb id i ty fa i lure a lso occurred at Mur ton works and twice at Fontburn works. Col lec t ive e nfo rcement was cons idered.

Recommended to improve maintenance pol ic ies and operat ional procedures across Lar t ington, Fontburn and Murton .


29 Jun 2015 For 0.5 hours (NNE)

Lar t ington works, Tees ide

100,000 High turb id i ty a t the out le t o f f i l te rs , compromis ing the d is in fect ion process .





Loss of contro l o f the t reatment f low through the process af fect ing mul t ip le t reatment s tages inc lud ing d is in fect ion.





88

Date and durat ion




29 Jun 2015 For 15 weeks (UUT)

Bury, Greate r Manchester

3 Petro l tas te or odour due to ground contaminat ion .


Issued a do not dr ink no t ice.


Suppl ied bot t led wate r .

Publ ic supply protected.

Service p ipe rep laced.

Surveyed neighbour ing propert ies to assess r isk .

Reviewed procedures . DWI comments and f indings:

Cr i t ica l o f company for inadequate invest igat ions in to the root cause, which gave r ise to a repeat compla in t f rom a consumer and for fa i l ing to not i f y the Inspectorate . Recommendat ions were made in respect o f the invest igat ion and not i f icat ion procedures .


30 Jun 2015 For 0.2 hours (NNE)

Murton works, Berwick area

15,000 Treatment fa i lu re: turb id i ty >1NTU in raw water supplying Murton works, wi th fa i lure of the automat ic shutdown system.






Fo l lowing e levated turb id i ty in Bleakr idge Borehole, one of s i x boreholes supplying Murton works, the automat ic fa i lsafe shutdown system fa i led to opera te. Turb id i ty in the t reated wate r remained below the l imi t o f 1 NTU because of b lending wi th other sources.




Northe rn reg ion

89

Date and durat ion




10 Ju l 2015 For 0.11 hours (NNE)

Fontburn works, Northumber land

122,200 Dis in fect ion compromised wi th turb id i ty greate r than 1NTU due to p lanned work .





Th is was a repeat event o f the previous event a t Fontburn works on 28 June 2015.

Loss of contro l o f the t reatment f low t hrough the process af fect ing mul t ip le t reatment s tages inc lud ing d is in fect ion.

S imi lar fa i lures occur red at Lar t ington and Murton and co l lec t ive enfo rcement was cons idered.

Recommended to improve maintenance pol ic ies and operat ional procedures across Lar t i ngton and Fontburn and Mur ton.


10 Ju l 2015 For 5 days (UUT)

Sut ton Hal l works, W irra l

371,567 Cryptospor id ium

detected fo l lowing loss of contro l o f c lar i f icat ion .




Review of procedures to inc lude adequate sampl ing in response to Cryptosprod ium detect ions.

Prevent wash water wi th turb id i ty >10NTU being returned to head of works.


The company fa i led to adequate ly i nvest igate, sample and react to process fa i lu res which resul ted in Cryptospro id ium de tect ions .

Enforcement cons idered but recommendat ions made requi r ing:

procedura l changes in response to adverse analyt ica l f ind ings; and

an engineer ing so lut ion to prevent tu rb id water re turn ing to the head o f the works.



90

Date and durat ion





Sweet loves works, Bol ton, Greate r Manchester

79,300 Dis in fect ion compromised due to loss of contro l o f pH correct ion .

United Uti l i t ies Water P lc act ion:

B lended supply wi th ano ther source.

Issued a boi l wate r not ice.

Provided an a l te rnat i ve supply by tanker/bowser . DWI comments and f indings:

Due to repeated occur rences of sub -opt imal d is in fect ion at s i tes operated by th is company, a works audi t was carr ied out .


The Inspectorate is addi t ional ly cons ider ing the of fence of fa i l ing to adequate ly t reat or d is in fect water .

Invest igat ion ongoing. Risk c lass i f icat ion: Majo r

21 Ju l 2015 For 2 hours (HPL)

Amerston works, v i l lage of W ynyard

433 Loss of supply fo l lowing automat ic works shutdown due to ch lor ine dos ing fa i lure.




The company responded quick ly to restore suppl ies af ter shut -down (which act i vated as des igned in response to low ch lor ine leve ls) .




Northe rn reg ion

91

Date and durat ion




24 Ju l 2015 For 2 days (YKS)

Centra l and west Shef f ie ld , Yorkshi re

56,000 Loss of suppl ies and brown d isco lourat ion fo l lowing burs t main .



Repai red main. DWI comments and f indings:

Sampl ing by the company was not proport ionate to the event o r populat ion af fected.

Suggested an increase in the number of samples. Risk c lass i f icat ion: Sign i f icant


Preston 1,750 Brown d isco lourat ion due to p lanned work .



P lanned and model led fo r repai r o f burs t main. DWI comments and f indings:

Valve iso la t ions were incorrect and contr ibuted to increased ve loc i t ies , which resul ted in d isco loured suppl ies .


28 Ju l 2015 For 5 days (NNE)

Hawthorn, County Durham

20 Boi l wate r not ice issued fo l lowing ingress of contaminated water a f ter repai r to a burs t main .


Sampled the af fected area.

Issued a boi l wate r not ice af ter ident i fy ing a r isk of backs iphonage f rom a horse t rough.

Emergency d is in fect ion of the system.

Boi l not ice l i f ted af ter rep lac ing the damaged ma in and service connect ions, and ins ta l la t ion of backf low protect ion on the supply to the horse t rough .


The company’s response to th is event was sat is factory and no fur ther DW I act ion wi l l be taken.



92

Date and durat ion




30 Ju l 2015 For 3 days (NNE)

Gunnerton works, Hexham

36,250 Atyp ica l Cryptospor id ium detect ion in f ina l water .


Invest igat ion samples taken at the works, i n the catchment area and in the d is t r ibut ion system.

Risk assessments were reviewed and sampl ing f requency increased at Gunnerton works .

The root cause was found to be assoc iated wi th sheep shear ing act iv i t ies in the catchment .




05 Aug 2015 For 3 months (UUT)

Frank law works; areas around Blackpool , Preston and Fleetwood

700,000 Cryptospor id ium . United Uti l i t ies Water Plc act ion:

Fo l lowing the Cryptospor id ium detect ions boi l water advice was issued.

The d is t r ibut ion ne twork was rezoned and f lush ing was conducted.

The Local Res i l ience Forum was engaged for support .

UV was ins ta l led at c r i t i ca l locat ions. DWI comments and f indings:

Invest igat ion ongoing. Risk c lass i f icat ion: Majo r

Northe rn reg ion

93

Date and durat ion




14 Aug 2015 For 30 hours (NNE)

Bedl ington 18,440 Brown d isco lourat ion due to p lanned work .


Repai red burs t main .

F lushed mains and returned to supply .

Sampled af fected a rea .

Review of procedures .


The company fa i led to f l ush the main adequate ly which resul ted in d isco loured suppl ies . The fa i lure was as a resul t o f poor r isk assessment and the company was s t rongly c r i t ic ised for no t learn ing f rom an ear l ie r even t and fa i l ing to update r isk assessment procedures.

Inadequate t ra in ing/competence of s ta f f . Risk c lass i f icat ion: Sign i f icant

27 Aug 2015 For 29 hours (NNE)

Lar t ington works, Mick le ton area

592,006 Detect ion of E.col i

in f ina l wate r .



E.col i detected in a rout ine sample. DWI comments and f indings:

The company were c r i t ic ised for fa i l ing to repor t the iso la te as E.col i .

The company fa i led to ident i fy the cause for th is fa i lure. Risk c lass i f icat ion: Sign i f icant


94

Date and durat ion




31 Aug 2015 For 2 hours (UUT)

W icken Hal l works, Rochdale, Greate r Manchester

34,045 Compromised d is in fect ion due to l ime dos ing pump mal funct ion .


Turb id i ty and ch lor ine a larms resul ted in a manual shut down of the works .

The works was restar ted to fac i l i ta te invest igat ion of the problem.

High pH f ina l wa ter was conf i rmed and so the works output was b lended wi th another sou rce.


Inadequate assessment o f the a larm condi t ions, preven ted ear ly detect ion of sodium hydroxide dos ing for pH correct ion of the f ina l water , which was a lso used for process contro l . High pH resul ted in improper ly d is in fected wate r .


Invest igat ion ongoing. Risk c lass i f icat i on: Sign i f icant

11 Sep 2015 For 7 hours (NNE)

Gateshead, Tyne and W ear

23,250 Brown d isco lourat ion due to contractor e rror .


Review of procedures. Improved i ts qual i t y assurance procedures and supervis ion of contracto rs .


Inadequate supervis ion of a contractor dur ing p lanned work permi t t ing the return of an unc leaned main being returned to supply .

Recommendat ions were made in respect o f :

management of contractors ;

competency and t ra in ing . Risk c lass i f icat ion: Sign i f icant

Northe rn reg ion

95

Date and durat ion





Town End, Sunder land

9,375 Brown d isco lourat ion fo l lowing p lanned work.


F lushed mains.


Repai red main.


Company to update r isk assessment and change method for p lanned works, to reduce rezoning act i v i t y, and has implemented measures to prevent a recurrence.


The Inspectorate was sa t is f ied wi th the company’s response.



Lar t ington works, Tees ide area

592,008 Compromised d is in fect ion due to p lanned work .



Dur ing the invest igat ion of the E.col i even t a t Lar t ington works on 27 August 2015, f lows were reduced in one contact tank compartment for inspect ion. The company was cr i t ic ised for inadequate pH and ch lor ine moni tor ing which fa i led to ident i f y increas ing pH due to overdos ing of l ime.

High ly cr i t ica l o f the lack of contro l over the s i te , enforcement act ion cons idered due to inadequate shut down processes.

Recommended to provide comprehensive cont ingency p lans for f ina l water qua l i ty assurance, inc lud ing a larm set po ints and shut downs.

Addi t ional l y cr i t ica l o f and recommended to prov ide assurance as to appropr ia te secur i t y for access contro ls on contact tank.



96

Date and durat ion




18 Sep 2015 For 3 days (UUT)

Macc lesf ie ld area

35,508 Brown d isco lourat ion due to p lanned work .



F lushed mains.



The company fa i led to fo l low the r isk assessment process and procedures and s ta r ted up a d is t r ibu t ion pumping s tat ion.

The outcome was to cause a main to burs t and the subsequent d isco lourat ion.

The company was cr i t ic i sed for :

inadequate communicat ion which caused a delayed response; and

fa i lure to mainta in cr i t ica l equipment .

Recommendat ions were made about operat ional procedures and r isk assessments .


29 Sep 2015 For 6 hours (UUT)

Ashworth Moor works, Rochdale, Greate r Manchester

21,956 Compromised d is in fect ion due to p lanned work .


Fo l lowing the a i r - lock ing of the d is in fectant dos ing system, sodium hypochlor i te was manual l y added to the contact tank.


Enforcement act ion is be ing progressed, in assoc iat ion wi th e ight o ther improper ly d is in fected wa ter events , to ensure robust systems, inc lud ing: process contro l ; po l icy and procedures; and asset improvement .

Invest igat ion ongoing.


Northe rn reg ion

97

Date and durat ion




07 Oct 2015 For 12 hours (UUT)

Cheadle 39,496 Loss of suppl ies and brown d isco lourat ion due to p lanned work .


F lushed mains.

Sampled af fected a rea . DWI comments and f indings:

The company fa i led to mainta in adequate mains records to permi t p lanned operat ion of va lves wi thout inc ident .

Recommended to implement an act ion p lan to ensure that geospat ia l records are up to date and ref lec t cor rect conf igurat ion of the mains and va lves.


19 Oct 2015 For 23 hours (UUT)

Clough Bot tom works, Burn ley, Lancashi re

17,615 Compromised d is in fect ion due to e levated f ina l wa ter pH.



F ina l water is ad justed for pH wi th the addi t ion o f sodium hydroxide. The dos ing contro l was no t conf igured to s top when f ina l water f low reduced below a set po int . Consequent l y a s lug of h igh pH water compromised d is in fect ion and entered supply when f low retu rned to normal .

Enforcement act ion is be ing progressed, in assoc iat ion wi th e ight o ther improper ly d is in fected wate r events , to ensure robust systems, inc lud ing: process contro l ; po l icy and procedures; and asset improvement .



98

Date and durat ion




23 Oct 2015 For 3 days (YKS)

Upperthong, Holmf i r th

7 ,500 Brown d isco lourat ion due to burs t t runk main .


Repai red main.

F lushed mains in a f fected area.


Reviewed procedures . DWI comments and f indings:

The company were s low to respond as increased f lows were thought to be due to p lanned f lush ing work in the vic in i t y.

Recommendat ions were made to the company to revi ew i ts in ternal communicat ions.


27 Oct 2015 For 3 days (NNE)

Port Clarance, Middlesborough

750 Do not d r ink not ice due to backs iphonage of industr ia l chemicals fo l lowing p lanned work.


Issued do not dr ink advice to 300 propert ies .

Provided bot t led wate r to af fected propert ies .

F lushed mains.


Protected the publ ic supply against b ackf low f rom the factory .


Consumer compla in ts of unacceptable taste and odour were the f i rs t ind icat ion of th is event , which was caused when the south main supply in to a major chemical fac tory was swi tched on to supp lement the n or th supply (normal ly on ly one operates at a t ime ). Fa i lure o f a cr i t ica l va lve and inadequate backf low protect ion resul ted in backs iphonage of potent ia l ly toxic ch emicals in to the publ ic supply.

Severe ly cr i t ic ised the company because of i ts whol ly inadequate response.

Served a Regulat ion 28 Not ice in order to p revent recurrence.

Risk c lass i f icat ion: Ser ious

Northe rn reg ion

99

Date and durat ion




28 Oct 2015 For 3 days (UUT)

Preston 156,000 Loss of supply and brown d isco lourat ion due to p lanned work at Whi tebul l service reservo i r .


F lushed mains.


Reviewed procedures.



10 Nov 2015 For 7 hours (NNE)

Thorpe works, Eas ington

7,090 Compromised d is in fect ion due to p lanned maintenance work .



F lushed mains to remove improper ly d is in fected water .

Reviewed procedures.


The company inappropr ia te ly d isabled a fa i l safe shutdown system to ca l ibra te a f low meter a l lowing undis in fected water to enter supply for 20 minutes.

Cr i t ic ised the company for a l lowing key fa i lsafe systems to be overr idden wi thout au thor isat ion, and wi thout any r isk assessment .

Recommendat ions were made requi r ing:

those s i tes where there i s a l ike l ihood of a s imi la r event and takes s teps to prevent any recurrences;

t ra in ing of works opera t i ves;

check ing and improving d is in fect ion contro l systems and a larm set t ings; and

implement ing procedures for seek ing author isat ion when making operat iona l changes.



100

Date and durat ion




17 Nov 2015 5 days (UUT)

Car l is le 17,500 Loss of suppl ies and brown d isco lourat ion fo l lowing damage to the in le t to High Brow reservo i r , caused by severe f looding.


Iso la ted in le t main.

Rezoned suppl ies where poss ib le .

A l ternat i ve suppl ies were provided by tanker.




F looding of the River Ca ldew fo l lowing heav y ra in destabi l ised the ground which damaged the in le t main to High Brow (Nelson) SR. The rezoning and tanker suppl ies act iv i t y consequent l y led to d isco loured suppl ies , demonstrat ing inadequate r isk assessments and turb id i ty moni tor ing.

The company were c r i t ic ised for the i r lack of f i l l i ng po int and tanker sampl ing and recommended to review the i r procedures and to inc lude turb id i ty as a moni to r ing requi rement .

Risk assessment to be reviewed and amended fo r mi t igat ion of hazards.


19 Nov 2015 2 days (UUT)

Blackpool 99,588 Ai r in water (whi te ) due to fau l ty leve l gauge at W arbreck Tower.




F lushed mains . DWI comments and f indings:

A fau l ty water leve l p ressure t ransducer a t W arbreck tower caused in termi t ten t operat ion o f the out le t pumps, resul t ing in a i r ent ra inment and 73 customer con tacts regard ing whi te water .

The company were c r i t ic ised for not su i tab ly p rotect ing external equipment and recommended to incorporate su i tab le measures to prevent pump operat ion caus ing aerat ion.


Northe rn reg ion

101

Date and durat ion




20 Nov 2015 For 3 days (NNE)

Whi t t le Dene works, Newcast le

1,846,926 Cryptospor id ium assoc iated wi th heavy ra in fa l l in the catchment area.


Sampled at the works and in the area suppl ied. DWI comments and f indings:

Publ ic Heal th England conf i rmed that there were no reported cases of c ryp tospor id ios is i l lness in the area suppl ied.

The Inspectorate was sa t is f ied wi th the company’s response.


20 Nov 2015 For 3 days (NNE)

Mosswood works, Sunder land

1,250,000 Cryptospor id ium assoc iated wi th heavy ra in fa l l in the catchment area .


Sampled at the works and in the area suppl ied. DWI comments and f indings:

The company’s response to th is event was sat is factory and no fur ther DW I act ion wi l l be taken. Publ ic Heal th England conf i rmed that there were no reported cases of cryptospor id ios is i l lness in the are a suppl ied.

The company p lans to rep lace the f i l ter media at Mosswood works commencing in 2016.



102

Date and durat ion




28 Nov 2015 For 5 hours (UUT)

Godley works, Hyde, Greater Manchester

503,075 Compromised d is in fect ion due to power in te rrupt ion and fa i lure of emergency back-up power supply.


Works shut down.



UPS fa i lure resul ted in phosphor ic ac id dos ing r ig shut t ing down and preven t ion of assoc iated a larms. Consequent e levated pH in the contact tank prevented ef fect i ve d is in fect ion. The improper ly d is in fected water cont inued to gravi ta t ional l y f low in to supply.



05 Dec 2015 For 4 days (UUT)

Br idge End works

8,000 Shutdown of Br idgend works near Keswick, due to heavy ra in fa l l and severe f looding.


Suppl ies were supported where poss ib le through rezoning , use of tankers to suppor t loca l reservo i rs and provis ion of bot t led wate r .

Sampl ing in a f fected areas fo l lowing restorat ion of suppl ies .


Loss of Br idge End works because of f looding of the works .

Works repai red and suppl ies re turned to normal .


Northe rn reg ion

103

Date and durat ion





Edenhal l works 4,542 Treatment fa i lu re – f looding of works due to adverse weather .






S i te was swi tched of f be fore f looding occur red. DWI comments and f indings:

Inadequate r isk assessment which had no t mi t iga ted the r isk of f looding .

S i te was par t o f a number of s i tes af fected by Storm Desmond s tar t ing wi th the in i t ia l not i f icat ion of Br idge End.

Mul t ip le p roblems wi th the s i te inc lud ing inadequate moni tors , UV, ch lor ine dos ing and d is in fect ion.



Keswick 3 Loss of suppl ies /poor pressure due to burs t main caus ing loss of supply and Cast ler igg SR to run dry fo l lowing heavy ra in fa l l and f looding.


Boi l advice issued to consumers in Cast ler igg , Borrowdale and Langwathby fo l lowing damage to water mains caused by f looding .


Company issued boi l wa ter advice where requi red.

Company were recommended to update p rocedures and record keeping fo r a l ternat ive supply vehic les .



104

Date and durat ion





Concess ionary supply

7 Issue of warn ing/bo i l wate r not ice due to raw water de ter iorat ion .


Deter iora t ing water qual i ty resul ted in bo i l water advice being issued.

A temporary a l ternat i ve supply was provided by tankers and bowsers.


The s to rm resul ted in increased turb id i ty a f fect ing the water in the Thi r lmere Aqueduct , which p rovides the concess ionary supply.

The company were c r i t ic ised for inadequate sampl ing and an unt imely per iod fo r the consumers to be suppl ied via a l ternat i ve means.



Glenr idd ing 468 Loss of suppl ies /poor pressure due to burs t main .


Boi l advice issued to consumers fo l lowing damage to water mains caused by f looding.


Company carr ied ou t repai rs and issued caut ionary bo i l water advice un t i l repai rs and bacter io log ica l samples were c lear .


Northe rn reg ion

105

Date and durat ion




18 Dec 2015 For 1 hour (YKS)

F ixby works, Huddersf ie ld area

70,000 Compromised d is in fect ion due to h igh turb id i ty water enter ing contact tank.



Restar ted works and inc reased ch lor ine res iduals at t reatment works.


A se ized va lve caused d i r ty washwater to backf low in to the t reatment process fo l lowing the loss of c lar i f i cat ion, leading to h igh tu rb id i ty water en ter ing the f ina l ch lor ine contact tank.

The company were c r i t ic ised by a l lowing the process contro l system to in i t ia te a f i l ter backwash when the fau l ty va lve was showing an a larm.

Enforcement act ion was cons idered, but the company has ins t igated capi ta l work to mi t igate the p roblem.


21 Dec 2015 For 1 month (UUT)

Lancaster 8 Do not d r ink not ice due issued to four propert ies .


Issued a do not dr ink no t ice to four p ropert ies fo l lowing compla in ts of petro l odour.


Provided temporary over land supply .

Re- la id supply p ipes in barr ier p ipework .


Root cause not conf i rmed but poss ib le permeat ion f rom local petro l s ta t ion. The company were cr i t ic ised for a s low invest igat ion and poor communicat ions wi th consumers, but commended for rep laceme nt of both the communicat ion and service p ipes.


Note: A complete table of events in England and W ales in 2015 can be found on the DW I webs i te ( www.dwi.defra.gov.uk ). I t is named Signif icant drinking water events in Engl and and Wales 2015.pdf .


106

Events in the Northern region outstanding from 2014 completed in 2015

Date and durat ion




15 Dec 2014 For 2 hours (UUT)

Hodder works, Lancashi re .

750,000 Dis in fect ion fa i lure .


Works was shutdown.

Repai red the fau l ty dos ing equipment and sampled the af fected area.

The company subsequent ly ins ta l led a fa i lsafe shutdown.


Chlor ine dos ing fa i led at both the in te rmediate and f ina l water s tage . The sodium hypochlor i te back -up system a lso fa i led. The company was cr i t ic ised for no auto -shutdown contro l and for not manual ly shut t ing the works down for over three hours .

Enforcement act ion is be ing progressed, in assoc iat ion wi th e ight o ther improper ly d is in fected water events , to ensure robust systems , inc lud ing: process contro l ; po l icy and procedures; and asset improvement .

Risk c lass i f icat ion: Ser ious

Northe rn reg ion

107

Annex 4 Planned drinking water quality improvements

Company Parameter, hazard or dr iver

Site Due for complet ion*

Status* Legal Instrument

DVW Pest ic ides Boughton 31-Dec-18 Ongoing Not ice

DVW Pest ic ides River Dee catchment 31-Mar-20 Ongoing Undertak ing

DVW pH Boughton 31-Dec-17 Ongoing Not ice

DVW pH L lwyn Onn 31-Dec-17 Ongoing Not ice

HPL I ron, turb id i ty, and manganese

Amerston Hal l 31- Ju l -18 Ongoing Not ice

HPL I ron, turb id i ty, and manganese

Hart lepool 31-Aug-17 Ongoing Not ice

NNE I ron and manganese

Tynes ide 31-Mar-17 Ongoing Undertak ing

NNE Lead Company wide 31-Mar-20 Ongoing Not ice

NNE Manganese Teesdale 31-Mar-18 Ongoing Undertak ing

NNE Meta ldehyde Broken Scar , Hors ley, Lumley, W arkwor th and W hi t t le Dean

31-Mar-20 Ongoing Undertak ing

NNE Risk of contaminat ion

Bi l l ingham and Middlesbrough Nor th

31-Ju ly-16 Ongoing Not ice

UUT Cryptospor id ium Frank law 31-Mar-16 Ongoing Not ice

UUT Cryptospor id ium Haweswater 31-Dec-16 Ongoing Not ice

UUT Cryptospor id ium Regional concess ionary supply 31-Jan-16 Ongoing Not ice

UUT Dis in fect ion Clough Bot tom 31-Jan-17 Ongoing Not ice

UUT Dis in fect ion Laneshaw Bot tom 31-Jan-17 Ongoing Not ice

UUT Dis in fect ion Lovec lough 31-Oct-16 Ongoing Not ice

UUT E.col i Brown Edge 31-Oct-18 Ongoing Not ice

UUT E.col i and

co l i forms Crosshi l l 31-Jan-18 Ongoing Not ice

UUT E.col i and co l i forms

Flaybr ick 30-Jun-16 Ongoing Not ice


Gorses ide 31-Mar-16 Ongoing Not ice


Prenton Lower 31-Mar-18 Ongoing Not ice

UUT I ron and manganese

Bi rkenhead d is t r ibut ion

31-Aug-16 Ongoing Undertak ing


Crosshi l l to W al lasey t runk mains

31-Aug-16 Ongoing Undertak ing


Cumwhinton to Car l is le mains

30-Apr-20 Ongoing Undertak ing


Hapsford d is t r ibut ion 31-Aug-16 Ongoing Undertak ing


Lytham dis t r ibut ion 31-Aug-17 Ongoing Undertak ing

UUT I ron, manganese, a lumin ium and pH

Telemet ry and a larms 31-Jan16 Delayed Undertak ing


108


Site Due for complet ion*

Status* Legal Instrument

UUT I ron, manganese, turb id i ty, co lour , t r iha lomethanes

Vyrnwy and Oswest ry 31-Jan-18 Ongoing Not ice

UUT Lead Dis t r ibut ion 31-Mar-20 Ongoing Not ice

UUT MCPA and to ta l pest ic ides

Wayoh 31-Aug-17 Ongoing Not ice

UUT MCPA, MCPP, meta ldehyde and to ta l pest ic ides

River Dee 31-Mar-20 Ongoing Undertak ing

UUT Meta ldehyde and to ta l pest ic ides

L langol len Canal catchment


UUT Taste and odour Lovec lough 30-Apr-18 Ongoing Not ice

UUT Taste and odour Sweet loves 30-Apr-18 Ongoing Not ice

YKS Col i form bacte r ia and E.col i

Cowick 31-Mar-16 Delayed Not ice


Heck 31-Mar-16 Delayed Not ice

YKS Colour and t r iha lomethanes

Chel low Heights – catchment

31-Mar-15 Completed 31-Mar-15

Undertak ing


Langset t – catchment 31-Mar-14 Delyaed Undertak ing


Loxley – catchment 31-Mar-14 Delayed Undertak ing

YKS Colour and t r iha lomethanes and DBPs

Langset t 31-Dec-19 Ongoing Not ice

YKS

Colour , DBPs, t r iha lomethanes and Cryptospor id ium

Rive l in 31-Dec-17 Ongoing Not ice

YKS DBPs, Cryptospor id ium , Pest ic ides

I r ton 31-Dec-18 Ongoing Not ice

YKS Lead Dis t r ibut ion 31-Mar-17 Ongoing Not ice

YKS Meta ldehyde

Lof tsome Br idge, I r ton, Huby, Eccup, Acomb Landing, Tophi l l Low and Elvington


YKS pH contro l Heading ley 31-Jan-17 Ongoing Not ice

*Dates used are those for the complet ion of the agreed programme of work. There is a fur ther per iod of 12 months before a programme is o f f ic ia l ly c losed to ascer ta in the benef i ts o f the work to consumers.

Northe rn reg ion

109

Annex 4.1 Delayed programmes


Site Reason for de lay

UUT I ron, Manganese, a lumin ium and pH

Telemet ry and a larms

Addi t ional ins t ruments and ins ta l la t ion work requi red in addi t ion to the or ig ina l work est imated.


Cowick Developments around panel l ing su i tab i l i t y, per iods for s i te shu tdown and broadband issues.


Heck

Developments around panel l ing su i tab i l i t y, per iods for s i te shu tdown and broadband issues. Addi t iona l work to be done on the boreholes.


Langset t – catchment

Problems wi th access rest r ic t ions to land.


Loxley Problems wi th access rest r ic t ions to land.


110

Annex 5 Competition in the water industry

The following table indicates the extent of competit ion in the water industry in England and Wales .

Inset appointments in place in 2015

Site Appointee Incumbent and region Status

Shotton Paper , Shotton

Alb ion W ater Dŵr Cymru W elsh W ater , Wales

Supplying water

Riss ington, Bour ton-on-the-Water

Alb ion W ater Thames Water, London and South East region

Supplying water

Buxted Chicken, Fl ix ton

Angl ian W ater Essex and Suf fo lk W ater, Centra l and Eastern region

Supplying water

W ynyard, near Wolviston

Har t lepoo l Water Nor thumbr ian W ater, Nor thern region

Supplying water

Brook lands, Mi l ton Keynes

Independent Water Networks Ltd

Angl ian W ater, Centra l and Eastern region

Supplying water

Great Bi l l ing W ay, Nor thampton



Supplying water

Long Crof t Road, Corby



Supplying water

Pr iors Hal l , Corby Independent Water Networks Ltd


Supplying water

Oakham North, Oakham


Severn Trent W ater, Central and Eastern region

Supplying water

Berryf ie lds , Aylesbury


Thames Water, London and South East region

Supplying water

Greenwich Mil lenium Vi l lage



Supplying water

Kings Cross, London



Supplying water

The Br idge, Dar tford



Supplying water

Media City, Salford Quays

Peel Water Networks Ltd

Uni ted Ut i l i t ies, Nor thern region

Supplying water

Norwich Common, W ymondham

SSE W ater Angl ian W ater Centra l and Eastern region

Supplying water

Emersons Green, Br isto l

SSE W ater Br isto l W ater , W estern region

Supplying water

L lani l id Park , South W ales

SSE W ater Dŵr Cymru W elsh W ater, Wales

Supplying water

Rivers ide, Bark ing SSE W ater Essex and Suf fo lk W ater, Centra l and Eastern region

Supplying water

Grayl ingwel l , Chichester

SSE W ater Portsmouth W ater, London and South East region

Supplying water

Newlands, Water loovi l le

SSE W ater Portsmouth W ater, London and South East region

Supplying water

Farndon Road, Market Harborough

SSE W ater Severn Trent W ater, Central and Eastern region

Supplying water

Northe rn reg ion

111


Hil ls Farm Lane, Horsham, Surrey

SSE W ater Southern W ater, London and South East region

Supplying water

Park Views, Epsom

SSE W ater Sut ton and East Surrey Water, London and South East region

Supplying water

Bromley Common, Bromley

SSE W ater Thames Water, London and South East region

Supplying water

Great Western Park , Didcot


Supplying water

Hale Vi l lage, Tottenham


Supplying water

Heart of East Greenwich


Supplying water

Kennet Is land, Reading


Supplying water

Kingsmere, Bicester


Supplying water

Marine W harf , Deptford


Supplying water

New South Quarter, Croydon


Supplying water

Nine Elms, London


Supplying water

Brewery Square, Dorchester

SSE W ater Wessex W ater, Western region

Supplying water

Old Sarum, Sal isbury


Supplying water

MoD T idworth near Andover

Veol ia W ater Projects

Wessex W ater, Western region

Supplying water

New inset appointments in 2015


Northstowe, Cambr idge

Angl ian W ater Cambr idge W ater, Centra l and Eastern region

Appointment granted

Woods Meadow. Oulton, Suf fo lk

Angl ian W ater Essex and Suf fo lk W ater, Centra l and Eastern region

Appointment granted

Marte l lo Lakes, Hythe


Af f in i ty W ater and Southern Water, London and South East region

Appointment granted

Cadley Hi l l , Swadl incote

South Staf fordshire Water

Severn Trent W ater, Central and Eastern region

Appointment granted

Cast le Way, Old Sarum


Appointment granted


112

Annex 6 Water company indices

Key

Dee Val ley Water (DVW)

Hart lepool Water (HPL)

Northumbrian Water (NNE)

Peel Water Networks (PWN)

United Ut i l i t ies (UUT)

Yorkshire Water (YKS)

Industry average (Industry)

Overall drinking water quality

Northe rn reg ion

113

Process control index

Disinfection index


114

Distribution maintenance index

Reservoir integrity

Northe rn reg ion

115

Annex 7 Glossary and description of standards

These def init ions wil l assist the understanding of the report where

technical terms have been used.

µg/l microgram per l i t re (one mil l ionth of a gram per l i t re) .

1,2-Dichloroethane is a solvent that may be found in groundwater in the v ic in ity of industr ia l s i tes . W here necessary i t can be removed by spec ia l water treatment . A European health-based standard of 3μg/ l appl ies.

Acrylamide European heal th-based s tandard. A chemical which is not normal ly found in dr ink ing water . I t is produced in the manufacture of polyacrylamides that are occasional ly used in water t reatment. I ts presence in dr ink ing water is l im ited by contro l of the product spec if icat ion. Standard is 0.1µg/ l .

Aesthetic assoc iated wi th the senses of taste, smel l and s ight .

Aggressive

a term used to indicate that the water has a tendency to d issolve copper (and other metals) f rom the inner surface of a p ipe or water f i t t ing such as a tap.

Alkali

a solut ion conta in ing an excess of f ree hydroxyl ions, wi th a pH greater than seven.

Aluminium occurs natura l ly in some source waters . I t is removed f rom dr ink ing water by convent ional water t reatment (coagulat ion and f i l t ra t ion) . Aluminium sulphate and polyaluminium chlor ide may be used as water treatment chemicals at some water treatment works. A nat ional standard of 200μg/ l appl ies.

Ammonium salts are natura l ly present in trace amounts in most waters. Their presence might indicate contaminat ion of sanitary s ignif icance and they interfere wi th the operat ion of the dis infect ion process. An indicator parameter wi th a guide value of 0.5mg/ l.


116

Analytical qual ity control (AQC)

procedures used to ensure that laboratory analys is methods are performing correct ly.

Antimony is rare ly found in dr ink ing water . Trace amounts can be der ived f rom brass tap f i t t ings and solders. A European heal th -based standard of 5μg/ l appl ies.

Aquifer water -conta ining underground s trata.

Arsenic occurs natura l ly in only a few sources of groundwater. Spec if ic water t reatment is required to remove i t . A European health -based s tandard of 10μg/l appl ies .

Benzene is present in petro l. I t is not found in dr ink ing water , but i t can migrate through underground p last ic water p ipes i f petro l is spi l t in the v ic in ity. A European health-based standard of 1μg/ l appl ies . Some bott led waters and sof t dr inks which inc lude sodium benzoate as an ingredient have been reported as conta ining benzene.

Benzo(a)pyrene is one of several compounds known as polycyc l ic aromat ic hydrocarbons (PAHs) . Their source in dr ink ing water is as a resul t of deter iorat ion of coal tar , which many years ago was used to l ine water pipes. Due to extens ive water mains refurb ishment and renewal i t is now rare to detect th is substance in dr ink ing water. A European health-based standard of 0.01μg/ l appl ies.

Boron in surface water sources comes f rom industr ia l d ischarges or f rom detergents in treated sewage ef f luents . The very low concentrat ions found in some dr ink ing waters are not a concern to publ ic heal th. A European heal th -based standard of 1mg/ l appl ies .

Bromate can be formed dur ing d is infect ion of dr ink ing water through a react ion between natura l ly occurr ing bromide and strong ox idants (usual ly ozone). I t may be generated in the manufacture of sodium hypochlor i te d is infectant . Except ional ly, groundwater can be contaminated wi th bromate, re leased f rom an industr ial s i te. A European health-based standard of 10μg/ l appl ies.

Bulk supply water suppl ied in bulk , usual ly in treated form, f rom one water company to another.

Northe rn reg ion

117

Cadmium is rare ly detected in dr ink ing water and trace amounts are usual ly due to d issolut ion of impur it ies f rom plumbing f i t t ings. A Europea n health-based s tandard of 5μg/ l appl ies .

Catchment

when used in connect ion wi th water , the catchment is the area dra ined by a r iver or water body.

Chloramination the process of generat ing a chloramine d is infectant res idual in water leaving a treatment works.

Chloramine a substance formed by a react ion between chlor ine and ammonia, used as a d is infectant in d istr ibut ion systems because of i ts long - las t ing propert ies compared to chlor ine.

Chloride is a component of common sal t . I t may occur in water natura l ly, but i t may also be present due to local use of de- ic ing salt or sal ine intrus ion. An indicator parameter with a guide value of 250mg/l .

Chlorine residual the small amount of ch lor ine or chloramines present in dr ink ing water to maintain i ts qual i t y as i t passes through the water company’s network of p ipes and household p lumbing.

Chromium is not present in dr ink ing water . A European health-based s tandard of 50μg/ l appl ies.

Clostridium perfringens is a spore-forming bacter ium that is present in the gut of warm-blooded animals . The spores can survive d is infect ion. The presence of spores in dr ink ing water indicates h is tor ic contaminat ion that requires invest igat ion. The standard is 0 per 100ml.

Coagulat ion a process employed dur ing dr ink ing water treatment to ass ist wi th the removal of par t icu late matter.

Coliform bacteria

are widely d istr ibuted in the environment of ten as a result of human or animal ac t ivi ty, but some grow on p lant mat ter . Their presence in a water supply indicates a need to invest igate the integr i ty of the water supply system. The s tandard is 0 per 100ml.


118

Colony counts are general techniques for detect ing a wide range of bacter ia, the types and numbers being dependent on the condit ions of the test . These counts , i f done regular ly, can help to inform water management, but they have no direct heal th s ignif icance. The s tandard is ‘no abnormal change’.

Colour occurs natura l ly in upland water sources. I t is removed by convent ional water treatment. A nat ional standard of 20mg/ l on the Plat inum/Cobalt (Pt /Co) scale appl ies .

Communicat ion pipe the connect ion f rom the water main to the consumer’s property boundary.

Compliance assessment a compar ison made by the Inspectorate of data gathered by water companies against standards and other regulatory requirements .

Compound a compound cons ists of two or more e lements in chemical combinat ion.

Concessionary supplies histor ica l f ree suppl ies of water for a householder , es tabl ished when a company wanted to lay mains across land and the landowner might agree, subject to a permiss ion, to take a supply of water f rom the main.

Conduct ivity is a non-spec if ic measure of the amount of natura l d issolved inorganic substances in source waters . An indicator parameter wi th a guide value of 2,500µS/cm.

Contact tank a tank, normal ly s i tuated on a treatment works s ite, which forms par t of the d is infect ion process. A d is infectant chemical (normal ly chlor ine) is dosed into the water as i t f lows into the tank. The per iod of t ime that the water takes to f low through the tank a l lows suf f ic ient ‘contact ’ t ime for the chemical to k i l l , or deact ivate, any v iruses or pathogenic organisms that may be present in the water.

Copper in dr ink ing water comes mostly f rom copper p ipes and f i t t ings in households. In general, water sources are not aggress ive towards copper, but problems very occasional ly occur on new hous ing estates. These ‘b lue water ’ events can be avoided by good p lumbing pract ices. A European health-based standard of 2mg/l appl ies .

Northe rn reg ion

119

Cryptosporidium is a paras ite that causes severe gastroenter i t is and can survive d is infect ion. I t is removed f rom water by convent ional processes for removing par t icu late mater ia l, and is inact ivated by u ltravio let l ight . In the UK, cont inuous moni tor ing is under taken at works c lass if ied by the company as being at s ignif icant r isk .

Cyanide is not present in dr ink ing water . A European health-based s tandard of 50μg/ l appl ies.

Dead leg refers to a p iece of p ip ing which is stopped of f at one end, but is connected to the supply at the other end and can result in stagnant water in the p ipework.

Distribution systems a water company’s network of mains, p ipes, pumping stat ions and service reservoirs through which treated water is conveyed to consumers.

Drinking Water Directive Counci l Direct ive 98/83/EC December 1998 – set t ing out dr ink ing water standards to be appl ied in member states.

Drinking water standards the prescr ibed concentrat ions or values l is ted in regulat ions.

Enforcement act ion the means, as set out in the W ater Act 1989 and consol idated into the W ater Industry Act 1991, by which the Secretary of State requires a water company to comply wi th certa in regulatory requirements.

Enterococci see Escher ichia col i .

Environment Agency the Environment Agency is respons ib le for mainta in ing and improving the qual i t y of f resh, marine, surface and underground water in England. Natura l Resources W ales i s the equivalent body in W ales.

Epichlorohydrin can be found in trace amounts in polyamine water t reatment chemicals. I ts presence in dr ink ing water is l im ited by contro l of the product spec if icat ion. A European heal th -based standard of 0.1μg/ l appl ies.

Epidemiology a process of s tudying the d istr ibut ion of cases of d isease wi thin a populat ion in re lat ion to exposure to poss ible sources of the infect ion, wi th a v iew to establ ish ing the actual source of the infect ion.


120

Escherichia col i and Enterococci

are bacter ia present in the gut of warm -blooded animals. They should not be present in dr ink ing water and, i f present , immediate act ion is required to ident i fy and remove any source of faecal contaminat ion that is found. The standard is 0 per 100ml.

Event

water companies have to inform the Inspectorate about occas ions when water qual i t y or suf f ic iency is af fected or when publ ic conf idence in dr ink ing water qual i ty may be impacted. The Inspectorate refer to these ins tances as ‘Events ’.

Filt ration where water is passed through a porous mater ia l (e.g. sand) to remove suspended part icu late matter .

Fluoride occurs natura l ly in many water sources, espec ial ly groundwater. I t cannot be removed by convent ional water treatment so h igh level s must be reduced by b lending wi th another low f luor ide water source. Some water companies are required by the local heal th author i ty to f luor idate water supplies as a protect ion against tooth decay. The dr ink ing water standard ensures levels are safe in e ither c ircumstance. Fluor idat ion of water is a Depar tment of Health pol icy. A European health-based s tandard of 1.5mg/ l appl ies.

Geosmin a substance produced by a var iety of natural ly occurr ing microbes, normal ly in surface waters which g ives r ise to a c haracter is t ic ‘ear thy’ or ‘musty’ tas te or odour .

Granular activated carbon an adsorbent f i l t ra t ion medium used to remove trace organic compounds f rom water .

Gross alpha/gross beta

radioact iv i ty in raw water can or ig inate f rom natura l substances or f rom a spec if ic point emission. W ater companies are required to screen for radionuc l ides that emit e ither a lpha or beta par t ic les . I f such screening exceeds guide values (gross a lpha 0.1Bq/ l , gross beta 1.0Bq/ l) then fu l ler analys is for spec if ic radionuc l ide s is carr ied out to determine the or igin.

Groundwater water f rom aquifers or other underground sources.

Northe rn reg ion

121

Hydrogen Ion

(pH)

gives an indicat ion of the degree of ac id i ty of the water . A pH of 7 is neutra l; va lues below 7 are ac id ic and values above 7 are a lkal ine. A low pH water may result in p ipe corros ion. This is corrected by adding an alkal i dur ing water t reatment. A specif icat ion of between 6.5 and 9.5 appl ies.

Improvement programmes water company improvement works, these are legal ly b inding on the company and each programme wi l l remedy an actual or potent ia l breach of a dr ink ing water s tandard wi th in a spec if ied t ime per iod.

Indicator organism an organism which indicates the presence of contaminat ion and hence the poss ib le presence of pathogens.

Indicator parameter something that is measured to check that control measures, such as water treatment , are work ing ef fect ive ly.

Information Letter formal guidance to water companies g iven by the Inspectorate and publ ished on the Inspectorate’s webs ite at ht tp:/ /www.dwi.gov.uk

Inspectorate The Dr ink ing W ater Inspectorate.

Iron is present natura l ly in many water sources. I t is removed by water treatment. Some iron compounds are used as water treatment chemicals. However, the commonest source of iron in dr ink ing water is corros ion of iron water mains. A nat ional s tandard of 200μg/l appl ies .

Lead very occasional ly occurs natura l ly in raw waters, but the usual reason for i ts presence in dr ink ing water is p lumbing in o lder propert ies. I f the water supply has a tendency to d issolve lead then water companies treat the water to reduce consumer exposure. The permanent remedy is for householders to remove lead p ipes and f i t t ings. The European heal th -based standard is 10μg/ l .

m3/d cubic metres per day.

Manganese is present natura l ly in many sources and is usual ly removed dur ing treatment . A nat ional standard of 50μg/ l appl ies .


122

Mean zonal compliance percentage

a measure of compl iance wi th dr ink ing water standards introduced by the Inspecto rate in 2004.

Mercury is not found in sources of dr ink ing water. A European health-based standard of 1μg/ l appl ies.

Methylisoborneol (MIB) a natura l substance produced by the growth of a lgae, normal ly in surface waters which g ives r ise to a character is t ic ‘earthy’ or ‘musty’ tas te or odour. I t is detected by the method for assessing tas te and odour .

mg/l mil l igram per l i t re (one thousandth of a gram per l i t re) .

Microbiological assoc iated wi th the study of microbes.

Ml/d megal i tre per day (one Ml/d is equivalent to 1,000 m

3/d , 1 mi l l ion l i t res /d or to 220,000

gal lons/d).

Nickel occurs natura l ly in some groundwater and where necessary spec ia l treatment can be insta l led to remove i t . Another source of nickel in dr ink ing water is the coat ings on modern taps and other p lumbing f i t t ings. A European health -based standard of 20μg/ l appl ies .

Nitrate occurs natura l ly in a l l source waters a l though h igher concentrat ions tend to occur where fert i l isers are used on the land. Nitrate can be removed by ion exchange water treatment or through b lending wi th other low ni trate sources. A European health-based standard of 50mg/ l appl ies .

Nitrite is somet imes produced as a by-product when chloramine is used as the essent ia l residual d is infectant in a publ ic water supply. Chloramine is the res idual d is infectant of choice in large d is tr ibut ions systems because i t is more stable and long- last ing. Carefu l operat ion of the d is infect ion process ensures levels of ni tr i te are kept below the standard. A European healt h-based s tandard of 0.5mg/l appl ies.

Notice

an ins truct ion served by the Secretary of State ( in the case of water suppl ies , the Chief Inspector of W ater) requir ing spec if ic act ions to be taken by the rec ip ient wi th in a spec if ied t imescale.

Northe rn reg ion

123

NTU nephelometr ic turb id ity uni t – the uni t of measurement for turb id ity in water

Odour can ar ise as a consequence of natura l processes in surface waters, par t icular ly between late spr ing and ear ly autumn. W ater treatment with act ivated carbon or ozone wi l l remove natura l substances caus ing taste. The s tandard relates to the evaluat ions of a panel of people assessing samples in the laboratory.

Ofwat the water industry’s economic regulator .

Oocyst the res istant form in which Cryptospor id ium occurs in the environment, and which is capable of caus ing infect ion.

Organoleptic character is t ics of a substance as detected by our senses, for example taste, odour or colour.

Ozone process (ozonation) the appl icat ion of ozone gas in dr ink ing water t reatment.

Parameters the substances, organisms and propert ies l is ted in Schedule 2 and Regulat ion 3 of the regulat ions. Parameter def in it ions can be found in th is g lossary.

Pathogen an organism which can infect humans and cause d isease.

PCV see ‘Prescr ibed concentrat ion or value’ .

Periodic review the economic regulator ’s process of sett ing water pr ices.

Pest icides any fungic ide, herbic ide, insect ic ide or re lated product (excluding medic ines) used for the control of pests or d iseases.

Pest icides – organochlorine compounds (aldrin, dieldrin, heptachlor, heptachlor epoxide)

are no longer used in the UK because they are pers is tent in the environment. They are not found in dr ink ing water . A European chemical standard of 0.03μg/ l for each compound applies .


124

Pest icides – other than organochlorine compounds

is a d iverse and large group of organic compounds used as weed k i l lers, insect ic ides and fungic ides. Many water sources conta in traces of one or more pest ic ides as a resul t of both agr icu ltura l and non-agr icu l tura l uses, main ly on crops and for weed contro l on h ighways and in gardens. Where needed, water companies have insta l led water treatment (act ivated carbon and ozone) so that pest ic ides are not found in dr ink ing water . W ater companies must test for those pest ic ides used widely in their area of supply. Pest ic ide monitor ing thus var ies according to r isk . A European chemical standard of 0.1μg/l for each indiv idual substance and 0.5μg/ l for the tota l of a l l pest ic ides appl ies .

Phosphate dosing t reatment of water that resul ts in a protect ive f i lm bui ld ing up on the ins ide of p ipes minimising the l ike l ihood of lead being present in dr ink ing water suppl ied through lead p ipes.

Plumbosolvency the tendency for lead to d issolve in water.

Polycyclic aromatic hydrocarbons

(PAHs)

is a group name for several substances present in petroleum-based products such as coal tar . (see Benzo(a)pyrene l is ted above for more informat ion) . A European health -based standard of 0.1μg/l for the sum of a l l the substances appl ies.

Powdered activated carbon (PAC)

powdered act ivated carbon is employed in treatment processes to remove pol lu tants.

Prescribed concentration or value (PCV)

the numerical va lue assigned to dr ink ing water standards def in ing the maximal or min imal legal concentrat ion or value of a parameter .

Private supply water suppl ied for human consumption or food product ion which is not provided by a water undertaker or l icensed water suppl ier .

Protozoan parasites a s ingle cel l organism that can only survive by infect ing a host, for example Cryptospor idium .

Public supply water suppl ied by a company l icensed for that purpose.

Raw water water pr ior to receiv ing treatment for the purpose of dr ink ing.

Northe rn reg ion

125

Regulations The W ater Supply (W ater Qual i t y) Regulat ions 2000 (England) and subsequent amendments , and the W ater Supply (W ater Qual i t y) Regulat ions 2010 (Wales).

Remedial act ion act ion taken to improve a s i tuat ion.

Remote operated vehicle (ROV)

equipment for inspect ing areas that are d if f icu lt to access, for example, inside tanks and p ipes.

Residual disinfectant the small amount of ch lor ine or chloramines present in dr ink ing water to maintain i ts qual i t y as i t passes through the water company’s network of p ipes and household p lumbing.

Risk assessment

a review under taken to ident i f y ac tual or potent ia l hazards to human heal th in a water treatment works and assoc iated supply system. Pr ior i t isat ion of r isk is based on cons iderat ion of l ikel ihood and consequence o f the r isk occurr ing.

Secretary of State Secretary of State for Environment, Food and Rural Af fairs .

Selenium is an essent ia l e lement and a necessary d ietary component . Amounts in dr ink ing water are usual ly wel l below the standard. A European health-based s tandard of 10μg/ l appl ies.

Service connect ion connect ion between the water company's main to a consumer’s property.

Service pipe any p ipe subject to mains water pressure or subject to mains pressure but for the c los ing of some valve.

Service reservoir a water tower, tank or other reservoir used for the s torage of treated water wi th in the d istr ibut ion system.

Suggested no adverse response level (SNARL)

a level of substance at which no adverse ef fects would be ant ic ipated.

Sodium is a component of common sal t . I t is present in seawater and brack ish groundwater . Some treatment chemicals contain sodium. Concentrat ions in dr ink ing water are extremely low, but some water sof teners can add signif icant amounts to dr ink ing water where they are ins ta l led in homes or factor ies. A nat ional standard of 200mg/ l appl ies.


126

Springs where water natura l ly emerges f rom below ground.

Sulphate occurs natura l ly in a l l waters and is dif f icu lt to remove by treatment. An indicator parameter with a guide value of 250mg/ l .

Supply pipe see service p ipe.

Supply point a point other than a consumer ’s tap author ised for the tak ing of samples for compl iance wi th the Regulat ions.

Surface water untreated water f rom r ivers, impounding reservoirs or other sur face water source.

Taste can ar ise as a consequence of natura l processes in surface waters, par t icular ly between late spr ing and ear ly autumn. W ater treatment with act ivated carbon or ozone wi l l remove natura l substances caus ing taste. The s tandard r elates to the evaluat ions of a panel of people assessing samples in the laboratory.

Technical audit the means of check ing that water companies are complying wi th their statutory obl igat ions.

Tetrachloroethane and Trichloroethene

are solvents that may occur in groundwater in the v ic in ity of industr ia l s i tes . W here necessary they are removed by spec ia l is t t reatment. A European health-based standard of 10μg/ l for the sum of both substances applies .

Tetrachloromethane is a solvent that may occur in gr oundwater in the v ic in i ty of industr ia l s i tes. Where necessary i t is removed by specia l is t water t reatment. A nat ional standard of 3μg/ l appl ies .

Time of supply the moment when water passes f rom the water company’s pipework in to a consumer’s p ipework.

Total indicat ive dose is a measure of the ef fect ive dose of radiat ion the body wi l l receive f rom consumpt ion of the water . I t is calculated only when screening values for gross a lpha or gross beta (radiat ion) are exceeded. An indicator parameter wi th a guide value of 0.10mSv/year.

Total organic carbon represents the tota l amount of organic matter present in water . An indicator parameter wi th a guide value of ‘no abnormal change’ .

Toxicology the s tudy of the health ef fects of substances.

Northe rn reg ion

127

Treated water water t reated for use for domestic purposes as def ined in the Regulat ions.

Trihalomethanes are formed dur ing d is infect ion of water by a react ion between chlor ine and natural ly occurr ing organic substances. Their product ion is minimised by good operat ional pract ice. A European health-based standard of 100μg/l appl ies .

Trit ium is a radioact ive isotope of hydrogen. Discharges to the environment are str ic t ly control led and there is a nat ional programme of monitor ing surface waters . An indicator parameter wi th a guide value of 100Bq/ l .

Turbidity is a measure of the c loudiness of water. At treatment works, measurement is an important non-specif ic water qual i t y contro l parameter because i t can be monitored cont inuous ly on - l ine and a larms set to a lert operators to deter iorat ion in raw water qual i t y or the need to opt imise water t reatment. An indicator parameter wi th a guide value of 1NTU. When detected at the consumer’s tap i t can ar ise f rom disturbance of sediment wi th in water mains. A nat ional s tanda rd of 4NTU appl ies in th is case.

Ultraviolet t reatment the use of ul travio let l ight to k i l l pathogenic microorganisms, for example Cryptospor idium .

Undertakings

Legally-b inding programmes of work agreed between a water company and the Chief Inspector of Dr ink ing Water to address actual or potent ia l water qual i t y issues, for complet ion wi thin a spec if ied t ime per iod.

Vinyl chloride may be present in p las t ic pipes as a res idual of the manufactur ing process of polyvinyl chlor ide (PVC) water p ipes. I ts presence in dr ink ing water is contro l led by product spec if icat ion. A European health-based standard of 0.5μg/ l appl ies .

Water supply zone a pre-def ined area of supply for establ ish ing sampl ing f requenc ies, compl iance wi th s tandards and informat ion to be made publ ic ly avai lable.

WHO World Health Organisat ion.

Wholesome/wholesomeness a legal concept of water qual i t y which is def ined by reference to s tandards and other requirements set out in the Regulat ions.

Drinking water2013Public water supplies in the Northern region of EnglandJuly 2014A report by the Chief Inspector of Drinking Water

Drinking Water Inspectorate | Nobel House, 17 Smith Square | London | SW1P 3JR | Tel: 0300 068 6400

www.dwi.gov.uk

drinking water 2015 · drinking water 2015 4 chapter 1: summary chapter 1: provides a summary of...

Documents