Inflow and Infiltration ( I & I) is mainly stormwater and groundwater that enters the sanitary sewer.During times of high rainfall, I & I rates increase and can cause wastewater treatment problems as well as flooding in the sanitary sewer system.
Cranberry Township specifically prohibits the discharge of "storm water, surface water, artesian well water, roof runoff, or subsurface drainage" to the sanitary sewer. Refer to the Code of Ordinances, Prohibited Discharge.
Infiltration is groundwater entering the sanitary sewer system through leaky manholes and cracked pipes (building laterals, collection sewers, and interceptor sewers).
Inflow is storm water entering the sewer system directly through connected roof gutters/downspouts, driveway drains, area drains, storm drains, storm sewers, foundation drains, or major defects in pipes.
Handling Inflow and Infiltration
The Pretreatment & Sewer Department actively pursues and addresses I & I to reduce the daily flow to the Brush Creek Wastewater Plant. We pinpoint I & I through the use of flow monitors, smoke and dye testing, physical inspections, or a closed-circuit television (CCTV). After evaluating the condition of the sewer collection system, maintenance practices such as manhole sealing or line rehabilitation are used to restore the sanitary line to working order.