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Item XX — Work Session <br />CITY OF ORONO MEMORANDUM <br />DATE: October 26, 2019 <br />TO: Orono City Council <br />FROM: Adam Edwards, P.E., Public Works Director / City Engineer <br />RE: Sanitary Sewer Service Line Point of Sale Inspection <br />1. Purpose. The purpose of this work session item is to discuss whether or not the City should develop <br />and adopt a Point of Sale Inspection Ordinance for Sanitary Sewer Service Pipe. . <br />2. Background. The City continues to work toward <br />reducing Inflow and Infiltration (I&I) into the City's <br />sanitary sewer system. Infiltration is clear water that <br />enters the sanitary sewer system through broken or <br />cracked pipes, defective joints, faulty connections, or <br />other defects in the mains, services, or manholes. Inflow is <br />clear water that enters the sanitary sewer system through <br />direct connections such as rain leaders, area drains, sump <br />r <br />pump connections, foundation drain tile, or <br />commercial/industrial discharges. (see illustration to right) <br />Excessive I/I can create backup problems as it <br />— <br />overwhelms our system, it is also very expensive. Orono <br />pays the Metropolitan (Met) Council to treat all of our <br />sewage. Sewage from the City flows into the Met Council <br />interceptor system and is routed to their treatment plants. <br />If clear water enters the sanitary sewer, we have to pay to <br />have it treated by the Met Council. This raises the sewer <br />I&I March & July 2019 <br />rates. I&I is monitored by the Metropolitan Council <br />Environmental Services (MCPS) The Cit 's bill is <br />Il Report for ORON0435 <br />Y <br />adjusted year to year based on the previous year's flows <br />going into the Met Council system. In addition the city is <br />fined for any exceedances of our flow allocations. The <br />exceedance warnings and fines are closely associated with i a ° <br />high rainfall events and saturated soils pointing to an I&I <br />issue (See charts at right). To date the vast majority of I&I <br />mitigation work has been on public infrastructure (pipes <br />and manholes) and while these have shown some <br />improvement there is still considerable I&I entering our <br />system. While there is still work to be done on the city <br />mains and manholes as key contributor to the I&I we are <br />experience is very likely the private service lines that <br />connect to our system. MCES estimates that as much as <br />80% of I&I may come from private sources. One method <br />of addressing I&I coming into the sewer system via private <br />service lines is with a point of sale inspection policy. <br />Several Communities within the metro area have <br />developed point of sale inspection policies/ programs. The <br />city does provide for inspections in our current ordinance however it is focused on illicit discharges into <br />