What is an illicit discharge?

An illicit discharge is essentially any discharge into a stormwater drainage system that is not composed entirely of stormwater. There are exceptions to this including water from firefighting activities and discharges from facilities already covered by a NPDES permit, such as treated sanitary sewer flows from a wastewater treatment plant. It is a common misconception that stormwater drainage flows to a wastewater treatment plant. However, this is not the case. Stormwater drainage flows, generally through pipes, and eventually outfalls to a wetland, river, stream, lake, pond, or directly to the ocean. Most stormwater flows receive minimal treatment, if any. Treatment for stormwater can include various methods of attempting to remove sediment materials and in some cases oils from water before it reaches a discharge. Illicit discharges can include cross-connections between sanitary sewer systems or private septic systems and the stormwater system, known or unknown, as well as anything that is dumped on the road or directly into a catch basin that includes materials other than stormwater. 

A main component of the Town's Stormwater Management Plan is Illicit Discharge Detection and Elimination (IDDE). The goal of an IDDE program is not necessarily punishment, but elimination of the illicit discharge. Many illicit discharges exist without the knowledge of the responsible party, and the Town can work with that party to eliminate the discharge. Sometimes illicit discharge isn't due to one party but to multiple individuals repeatedly and hopefully unknowingly doing something they shouldn't do. An example of this would include improper disposal of pet waste. Often a person walking their dog either doesn't clean up after it, or properly bags their dog's waste, but then drops it in a catch basin rather than waiting to find a trash barrel. Now the stormwater system is contaminated not only with dog waste but also with plastic bags. Many catch basins are therefore marked in some way to warn people not to dump anything in them. In Rockport, this is generally done in one of two ways. Newer catch basin grates may have "No Dumping" stamped in the cast iron grate. Catch basins without the newer style grate often are painted nearby with a stencil that reads "Dump No Waste - Drains to Ocean".

Show All Answers

1. What is Stormwater?
2. What is NPDES?
3. What is an illicit discharge?
4. What is Municipal Good Housekeeping?
5. What can I do to assist with Municipal Good Housekeeping?