Infiltration is groundwater that enters the sanitary sewer system through leaky manholes and cracked pipes (building laterals, collector sewers, and interceptor sewers).
Inflow is storm water that enters the sewer system through directly connected roof gutter downspout, driveway drains, area drains, storm drains, storm sewers, foundation drains, or major defects in pipes.
I & I is mainly clear water that is not meant to be treated at the wastewater treatment facility, and is a constant challenge for all wastewater system operators. 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 Code of Ordinances, Prohibited Discharge