What is inflow and infiltration (I/I)?
A. Inflow and infiltration (I/I) are terms used to describe the ways that groundwater and stormwater enter the sanitary sewer system. Inflow is water that enters the sewer through direct (improper) connections, such as roof downspouts, driveway and foundation or curtain drains. Infiltration is groundwater that leaks into the sewer system through cracks in the service lateral or mainline pipe, manhole or separated pipe joints.
