Inflow is water from a sump pump or roof drain. This relatively clean water should be connected and discharged to a storm water system. In some cases, homeowners connect sump pumps (illegally) to the sanitary sewer because it is relatively easy and inexpensive.
Infiltration is groundwater that seeps directly into sanitary transmission systems, usually during the spring heavy rains and melting snow.
The City of St. Johns Wastewater Treatment Facility receives an average daily flow of 1.3 million gallons of wastewater from residents and businesses within the City and portions of Bingham Township. Our facility provides tertiary treatment utilizing biodisks and filtration technology.
We initiated many improvements with a construction project that began in July 2008 at the St. Johns facility. We implemented a very practical design to limit the cost for our community. At the same time, replacing old equipment, rerouting portions of the flow to gain wet-weather capacity further increased efficiencies throughout the processes.
We welcome the opportunity to explain the operation and regulations/requirements we must achieve at your public-owned wastewater treatment facility.

Informational Website
http://ga.water.usgs.gov/edu/wuww.html