SOUTH WEST WATER

PenInsula House Rydon lane Exeter Devon Eng land EX2 7HR Tel 01392 446688 Fax 01392 434966 soulhwestwatercouk

Andrew Chesworth Direct line 01392 443260 Ofwat Email Irowesouthwestwatercouk Centre City Tower Fax 01392 443260 7 Hill Street Our ref RAGsLR Birmingham B54UA

23 September 2013

Dear Andrew

REQUEST FOR INFORMATION - THAMES WATER lOOK

Further to your letters dated 6 and 13 September July 2013 regarding the request of information following Thames Water lOoK submission we have included the following responses to each of your requests

South West Water Limited Registered in England No 2366665 A subsidiary of Pennon Group Plc Registered Office Peninsula House Rydon Lane Exeter EX2 7HR

Sewer Flooding

The extreme wet weather in 201213 has inevitably impacted the number of customers at risk of flooding South West Water are investing to reduce the number of our customers at risk The detailed data and commentary requested has been included in Appendix B In line with the guidance we can confirm that this excludes any impact of private sewers

Transferred Private Sewers

We can confirm that the costs entered within the August Submission for Transferred Private Sewers relates to total spend on the adopted sewer network only South West Water have completed detailed reviews of the costs and activity on these assets since their transfer

These costs exclude any uplift in the activities which may have arisen on the public (pre-existing) network

Yours sincerely

Louise Rowe Corporate amp Central Finance Manager

2

Sewer Flooding Appendix B

Line Decription Units DPs 2011-12 2012-13 2013-14 2014-15

1 Total 1 in 10 and 2 in 10 properties on the register at end of year nr 0 37 60 52 402 Added because of better information nr 0 4 26 10 103 Removed because of better information nr 0 0 0 5 54 Removed by company action nr 0 5 3 13 17

Line 1 ndash Total 1 in 10 and 2 in 10 properties on the register at end of year The forecast of 40 K5 is above the K5 target (of 30) as a result of the abnormally wet weather in 2012 which saw a dramatic rise in the number of flooding incidents in the region River flows and groundwater levels both reached exceptionally high levels increasing the likelihood of flooding for many homes and businesses The number of internal sewer flooding incidents therefore increased dramatically in the year with nearly four times as many repeat floodings in 201213 compared to previous years There was therefore a large increase in additions to the Register for 201213 as shown in Line 2 Had 201213 been a typical year for DG5 floodings there is no doubt we would now be on track to meet the K5 Register target of 30 When our investigations into schemes for register removals are complete we may be in a position to revise the forecast closer to or at the K5 target but we cannot confidently do this at this time Line 2 ndash Added because of better information In 201314 there have been 7 additions to the 2 in 10 Register in the year to date all are properties that flooded in 201213 and were on the 1 in 20 Register at the end of that year The forecast number of additions has been estimated at 10 in each of 201314 and 201415 however this may change depending on the outcome of investigations South West Waterrsquos policy is that no properties are added to our DG5 Registers as a result of sewer modelling information all properties on the Register have flooded The definition applied of internal sewer flooding is any spillage of sewage internal to a property including under suspended floors and this includes backflow of sewage contained by baths and shower trays Line 3 ndash Removed because of better information It is anticipated that some of the properties on the Register particularly those added as a result of the extreme weather in 201213 may subsequently be shown by modelling to be not at risk of hydraulic overload greater than 1 in 20 years If this is the case then they will be removed from the Register because of better information This has been estimated as 10 properties in total in the next two years We have added properties to the Register where there is any doubt as to the cause to ensure that a detailed investigation is carried out Line 4 ndash Removed by company action We have increased our DG5 removal programme in the last two years of K5 to attempt to recover the position after the large number of additions to the Register in 201213 We are now investigating potential solutions there is a tight timescale for achieving a significant number of removals by the end of K5 to be as near as possible to our K5 target

1

Sewer Flooding Appendix B

Line Decription Units DPs 2011-12 2012-13 2013-14 2014-15

1 Total 1 in 10 and 2 in 10 properties on the register at end of year nr 0 37 60 52 402 Added because of better information nr 0 4 26 10 103 Removed because of better information nr 0 0 0 5 54 Removed by company action nr 0 5 3 13 17

Line 1 ndash Total 1 in 10 and 2 in 10 properties on the register at end of year The forecast of 40 K5 is above the K5 target (of 30) as a result of the abnormally wet weather in 2012 which saw a dramatic rise in the number of flooding incidents in the region River flows and groundwater levels both reached exceptionally high levels increasing the likelihood of flooding for many homes and businesses The number of internal sewer flooding incidents therefore increased dramatically in the year with nearly four times as many repeat floodings in 201213 compared to previous years There was therefore a large increase in additions to the Register for 201213 as shown in Line 2 Had 201213 been a typical year for DG5 floodings there is no doubt we would now be on track to meet the K5 Register target of 30 When our investigations into schemes for register removals are complete we may be in a position to revise the forecast closer to or at the K5 target but we cannot confidently do this at this time Line 2 ndash Added because of better information In 201314 there have been 7 additions to the 2 in 10 Register in the year to date all are properties that flooded in 201213 and were on the 1 in 20 Register at the end of that year The forecast number of additions has been estimated at 10 in each of 201314 and 201415 however this may change depending on the outcome of investigations South West Waterrsquos policy is that no properties are added to our DG5 Registers as a result of sewer modelling information all properties on the Register have flooded The definition applied of internal sewer flooding is any spillage of sewage internal to a property including under suspended floors and this includes backflow of sewage contained by baths and shower trays Line 3 ndash Removed because of better information It is anticipated that some of the properties on the Register particularly those added as a result of the extreme weather in 201213 may subsequently be shown by modelling to be not at risk of hydraulic overload greater than 1 in 20 years If this is the case then they will be removed from the Register because of better information This has been estimated as 10 properties in total in the next two years We have added properties to the Register where there is any doubt as to the cause to ensure that a detailed investigation is carried out Line 4 ndash Removed by company action We have increased our DG5 removal programme in the last two years of K5 to attempt to recover the position after the large number of additions to the Register in 201213 We are now investigating potential solutions there is a tight timescale for achieving a significant number of removals by the end of K5 to be as near as possible to our K5 target

1