Town of Groton
Illicit Discharge Detection and Elimination Program
As part of the SWMP, the Town is required to develop, implement and enforce a plan to detect and eliminate existing illicit discharges to the storm sewer system. Illicit discharge is defined by the Connecticut DEP in their general permit as “any unpermitted discharge to waters of the state that does not consist entirely of stormwater or uncontaminated groundwater except the following: landscape irrigation; uncontaminated groundwater discharges such as pumped groundwater, foundation drains, water from crawl space pumps and footing drains; irrigation water; lawn watering runoff; residual street wash water; discharges or flows from fire fighting activities; and naturally occurring discharges.”
Illicit discharges can come from the following places:
• A leaking sanitary sewer line into a cracked storm sewer line or a cross-connection between the two;
• A direct connection from a building drain (sewer in house) to the storm sewer system;
• A shop floor drain that is connected to the storm sewer; and
• Pollutants (such as motor oil, gasoline, antifreeze, pet waste, cigarette butts, cleaning products, pesticides,
fertilizers and trash) that have been dumped illegally into a catch basin.
In order to begin the Illicit Discharge Detection and Elimination (IDDE) Program, the Town first developed a map of the storm sewer system in 2004 showing the location of all outfalls (12” in diameter or greater) and the names and location of all waters within the Town of Groton that receive discharges from those outfalls. An outfall is the end of the storm sewer pipe where the water runs out. There are approximately 885 outfalls in the Town of Groton.