Illicit Discharge Detection & Elimination

An illicit discharge is the discharge of pollutants or non-stormwater materials into the storm drainage system via overland flow, direct dumping, or illicit connections. Illicit connections are pipes or other direct connections that illegally or unknowingly release pollutants or non-stormwater materials into a storm drainage system or directly into a body of water.

Under the NPDES-MS4 Permit, the Town of Sudbury is required to implement an Illicit Discharge Detection and Elimination (IDDE) Program to ensure that all discharges to and from the municipal separate storm drainage system that are not composed entirely of stormwater are either permitted by the Massachusetts Department of the Environmental Protection (DEP) or eliminated.

Illicit Discharge Detection and Elimination (IDDE) outfall inspections program information

Department of Public Works letter to Residents

Sudbury’s Commitment to Clean Water Flyer 

Examples of Illicit Discharges

  • Bagged pet waste
  • Direct septic connections into the storm drain system
  • Improper disposal of automobile and household products
  • Laundry wastewater
  • Leaves and other debris dumped into open drainage and stream channels
  • Overflow from septic tanks, car wash wastewater
  • Sanitary wastewater from crushed or collapsed pipes or surcharges


Exceptions (Not Considered Illicit Discharges)

  • Dechlorinated swimming pool discharges
  • Diverted stream flows
  • Foundation drains
  • Landscape irrigation
  • Potable water source discharges
  • Rising or out-breaking groundwater
  • Stormwater runoff from streets and sidewalks
  • Uncontaminated pumped groundwater (includes clean sump pump discharges)
  • Water line flushing

For more information regarding the Phase II Stormwater Management Program, contact the Sudbury Department of Public Works at (978) 440-5421.

More Information