What is an Illicit Discharge?

A municipal separate storm sewer system (MS4) refers to the system of pipes, ditches, and/or gullies, managed by a government entity, used for stormwater collection and distribution. The release of non-stormwater discharge into a stormwater sewer system, either accidentally or purposely, is considered an illicit discharge. Illicit discharges enter the stormwater sewer system through direct or indirect connections. An example of a direct connection is wastewater piping connected to a stormwater drain. An example of an indirect connection is dumping oil straight into a stormwater drain.

What are the Sources of Illicit Discharges?

• Sanitary wastewater
• Car wash wastewater
• Improper oil disposal
• Radiator flushing
• Laundry wastewater
• Spills from roadway accidents
• Improper disposal of auto and household toxins
• Improper disposal of yard waste, such as leaves

These Illicit discharges flow, untreated, into the Chesapeake Bay through the town’s streams, rivers and ponds, resulting in poor water quality conditions. These water bodies potentially serve as local drinking water sources, habitat for wildlife, and recreational areas used for swimming, boating and fishing. When polluted stormwater enters a storm drain, it is released into a water body, such as a stream. Eliminating illicit discharges is a key component to protect water quality.

How do I know if I’ve seen an illicit discharge?
5 Question Checklist for illicit discharge identification

1. Does the liquid have a distinct color?
   Since water is most often clear, the most obvious sign of an illicit discharge is the coloration of water. These colors can range from milky white, to fluorescent orange. If you see colors like these don’t hesitate to call our illicit discharge hotline.
2. Does the liquid have a distinct smell?
   Chemicals such as gasoline, anti-freeze, detergents, and household cleaners have highly recognizable smells. If you smell any unfamiliar scent being discharged from a storm drain, catch basin, pond, or swale, please do not hesitate to call our illicit discharge hotline.
3. Is there any smoke or bubbling?
   In most cases, smoking and or bubbling is the result of a chemical ingredient reacting with another source. If you see smoke or bubbling around a storm water facility (i.e. storm drain, catch basin, pond, or swale) please call our illicit discharge hotline.
4. How much is being discharged?
   The severity of an illicit discharge depends on the amount of a pollutant present in a storm water facility (more chemicals, means more damage being done to that particular facility).
5. How long have you noticed the discharge?
   The more time a hazardous chemical has to infiltrate a storm water facility the more widespread it’s likely to become. So as soon as think you’ve spotted an illicit discharge, ask yourself these questions and don’t hesitate to call.