The illicit discharge detection and elimination (IDDE) minimum control measure consists of best management practices (BMPs) and program elements that focus on finding and addressing non-stormwater discharges and/or non-permitted discharges that may be entering the municipal separate storm sewer system (MS4).
llicit discharges can come from a wide-range of sources including illegal dumping of paints, hazardous wastes, and wash-water, as well as improper connections of sanitary sewer lines or laundry waste to the stormwater system. Illicit discharges can seriously degrade water quality and are a widespread problem especially in commercial and other high risk areas. However, because these sources are intermittent, and sometimes not visible, they often go undetected.