Disclaimer: The BMP examples and references included on these fact sheets are not intended to be comprehensive. Additionally, the list of BMPs is not all-inclusive, and it does not preclude MS4s from using other technically sound practices.

In general, illicit discharges include any discharge into a storm drain system that is not entirely composed of stormwater. The exceptions include water from firefighting activities and discharges from facilities already under an NPDES permit. Illicit discharges are a problem because, unlike wastewater, which flows to a treatment plant, stormwater generally flows to waterways without any additional treatment. Illicit discharges often contain pathogens, nutrients, surfactants, and various toxic pollutants.

Phase II MS4s are required to develop a program to detect and eliminate these illicit discharges. This primarily includes developing:

• a storm sewer system map,
• an ordinance prohibiting illicit discharges,
• a plan to detect and address these illicit discharges, and
• an education program on the hazards associated with illicit discharges.

An effective illicit discharge program needs to be both reactive and proactive. The program is reactive in addressing spills and other illicit discharges to the storm drain system that are found. The program must also be proactive in preventing and eliminating illicit discharges through education, training, and enforcement.

Key BMPs and Resources

• Stormwater Phase II Fact Sheet on the IDDE Minimum Measure
• Illicit Discharge Detection and Elimination: A Guidance Manual for Program Development and Technical Assessments - Center for Watershed Protection's comprehensive manual that includes details on creating and managing an IDDE program, implementation timelines, information on estimating program costs in terms of capital and personnel expenses, and types of testing used to detect stormwater illicit discharges.
• Illicit Discharge Detection and Elimination Program Development BMP Fact Sheet - EPA is updating this fact sheet. You can request a copy by sending an email. 

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BMP Fact Sheets

EPA is updating the following fact sheets. You can request a copy or recommend any changes by filling out and submitting the form at the bottom of the NPDES Contact Us webpage.

The fact sheets describe the BMPs and generally provide applicability, implementation, and effectiveness information to help municipal stormwater and construction site operators comply with the stormwater Phase II requirements.

Developing an IDDE Program

• Illicit Discharge Detection and Elimination Program Development
• Reducing the Occurrence of SSOs

Trash and Illegal Dumping

• Developing a Used Oil Recycling Program
• Illegal Dumping Control
• Trash and Debris Management

Decentralized Wastewater

• Preventing Septic System Failure
• Sewage from Recreational Activities

Public Reporting

• Community Hotlines

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Resources

EPA

• Trash Free Waters website  - Resources to educate the public about the impact of trash and ways to prevent marine debris.
• Non-Stormwater Discharges  - Fact sheet on controlling Non-Stormwater Discharges to the storm drain system.
• Model Illicit Discharge Ordinance
• Wastewater Education Materials - Materials to help municipal officials educate citizens on important wastewater issues.

Other

• Examples of municipal programs to detect and eliminate illicit discharges:
  • Wayne County, Michigan Exit(13 pp, 106 K, About PDF)
  • Manchester, New Hampshire Exit
• Example materials created for businesses:
  • Business and Industry Guide to Chesterfield County’s Illicit Discharge Ordinance Exit(2 pp, 112 K, About PDF) – Chesterfield County, Virginia
  • Best Management Practices: Food-Related Cleaning Exit – Las Vegas, Nevada

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