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Ordinance 76-O-12: Subsoil Drain Pipe

Proposed Modifications Regarding

New Sump Pump Discharges

September 24, 2012

Proposed modification would only affect new sump pump discharges

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Location of Existing Storm Sewers

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Revised ordinance would provide four key benefits to the City

1. Help prevent sewage backups during rain events.

2. Make code consistent with current policy and other sections of the code.

3. Minimize the environmental impacts of sump pump discharges.

4. Defines requirements to obtain permission to connect to the sewer system

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Preventing sewage backups during rain events

Relief sewer improvements and restrictors successfully reduced basement backups resulting from surface runoff.

Sump pumps directly connected to the combined sewers still have the potential to cause basement backups.

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Preventing sewage backups during rain events

63% of combined sewers are ≤ 12” diameter.

At an average slope of 0.4%, the capacity of a 12” sewer is about 744 gpm.

Typical sump pump capacity is 40 gpm 18 sump pumps could overwhelm an entire 12” sewer.

Therefore, 12” and smaller combined sewers act mostly as sanitary sewers, with limited capacity for sump pump discharges.

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Consistency with City policy and other portions of the City Code

“Footing drains shall be connected to the sump pump and discharge shall be made to the storm or combination sewers, and not to sanitary sewers.”

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Environmentally friendly policy

Assuming 30 minutes of sump pump operation and 40 gpm capacity, every 1,000 sump pumps would discharge 1.2 million gallons of clear water to the combined sewer during a rain storm.

1.6 million tons of CO2 is produced for every 1,000 sump pumps operating during a rain storm (for pumping and treatment at MWRD facilities)

More environmentally responsible to discharge to the ground surface and allow at least a portion of the flow to infiltrate into the soil before it reaches street inlets.

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Proposed revisions include a clearly laid out waiver policy

Community & Economic Development, Public Works, and Utilities Departments collaborated to clarify waiver policy.

Ordinance provides clearly defined requirements to obtain permission to connect to the sewer system.

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QUESTIONS

Ordinance 76-O-12: Subsoil Drain Pipe

Proposed Modifications Regarding

New Sump Pump Discharges

September 24, 2012