What Is An Illicit Discharge?

An illicit discharge is the discharge of pollutants or non-stormwater materials into a storm drain system via an illegal pipe connection or other direct tie-in and also via overland flow or direct dumping into a catch basin or storm drain. Municipal storm drains are intended to convey storm water runoff to nearby lakes and streams to prevent flooding, but they are not intended to carry flow from sources such as sanitary sewer systems, carwashes, Laundromats, or other similar sources. Illicit discharges are a problem because stormwater generally flows to a river, pond, or stream without any additional treatment, unlike wastewater or sewer which flows to wastewater treatment plants. Dumping anything other than stormwater into a storm drain is illegal and considered an illegal discharge.