Inflow & Infiltration Defined
Inflow and Infiltration are terms used to describe the ways that groundwater and storm water or “clear water” enters the sanitary sewer system. Inflow is surface water that enters the sewer system from yards, roof and footing drains, cross-connections with storm drains, downspouts, and through holes in manhole covers. Infiltration is groundwater that enters sewer pipes through holes, breaks, joint and connection failures, and other openings.