Sanitary Sewer Overflow

Overflow of sanitary sewage, mixed with stormwater, to a stream, from the separate sanitary sewer system in times of wet weather due to the entry of extraneous water into the System. These wet weather overflows occurs when the sewers become hydraulically overloaded. By-passes are usually designed and are used to prevent back-ups into basements. Dry weather overflows occur form maintenance-related reasons, such as a blockage or pipe failure.