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What is I&I?

Inflow and Infiltration DiagramInflow
A direct connection of clear water into the wastewater collection system.

Inflow is by far the larger problem and occurs in direct proportion to rainfall. Inflow is usually traced to sump pumps (used by many homeowners to keep groundwater out of basements), roof downspouts and foundation drains that are connected to the City’s sanitary sewer system. Sump pumps are often connected to the sanitary sewer system via a hose leading from the sump to a laundry tub or a floor drain.

State law requires sump pumps, foundation drains and roof down spouts to be connected directly to a storm sewer or onto the ground, not to the sanitary sewer system.

An indirect connection of clear water to the wastewater system.

Infiltration occurs when groundwater seeps into sewer pipes through cracks, leaky joints or deteriorated manholes.

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