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Illicit Discharge Detection and Elimination Manual

A Handbook for Municipalities

Polluted stormwater runoff is commonly transported through municipal separate storm sewer systems, known as MS4s. Illicit discharges are non-storm water discharges into MS4s, for example from a home’s sanitary wastewater pipe that has been mistakenly connected to the storm sewer system.

Detection and elimination of these discharges is one of the six mandatory pollution control measures required of operators of regulated small MS4s by EPA’s Phase II storm water regulations.

This manual provides and overview and useful tools to aid operators of regulated small municipal separate storm sewer systems (MS4s) in complying with a key element of EPA’s NPDES Phase II Storm Water Program: illicit discharge detection and elimination (IDDE).