Illicit Discharge Detection & Elimination (IDDE)

Be careful - many discharges are dangerous!

The Illicit Discharge Detection and Elimination (IDDE) Program requires CDOT implement a program to detect and remove (or advise the discharger to the MS4 to obtain a separate CDPS permit for) illicit discharges and improperly disposed materials into the MS4.

CDOT detects and removes illicit discharges to its storm drain system. More information can be found in the following documents.

Information on tracing, removing, and enforcement of Illicit Discharges can be found in the Illicit Discharge Program Manual.

CDOT seeks to detect and eliminate all illegal discharges. An illegal discharge, often called an illicit discharge, is a discharge to CDOT's storm drain system that could cause pollution. Common pollutants include oil and grease, fertilizers and pesticides, grass clippings and leaves, and any substances that have a "funny" smell or color.

Learn more by accessing the Illicit Discharge Program factsheet.

What to Report

Oil, gas, etc. entering a storm drain inlet Soap suds or anything with a "funny" color or odor exiting a storm drain pipe Chemicals spilled
on a highway
Sediment from an unknown source entering a waterway

Oil gas enter storm drain outlet

Soap suds exiting a storm drain

Chemicals spilled on highway

Sidiment for unknown source

Tips for reporting illegal discharges

  • Estimate the amount of discharge
  • Note the characteristics of the discharge (color, odor, etc.), never get too close to a strange discharge because it can be dangerous
  • If applicable and possible, take information on the vehicle dumping the waste

Remember: Storm sewers collect and route surface runoff to local surface waters. Storm sewers do not remove pollutants or otherwise provide water quality treatment. Anything that enters a storm sewer will flow to local surface waters. Sanitary sewers, in comparison, collect and route wastewater to the wastewater treatment plant for pollutant removal and treatment.

Storm drain system