National Pollutant Discharge Elimination System (NPDES)

The Federal Clean Water Act requires that municipalities must comply with the U.S. Environmental Protection Agency’s (EPA) NPDES II program. The goals of the National Pollutant Discharge Elimination System (NPDES) program are to preserve, protect, and improve water quality resources by reducing pollutants in stormwater runoff.

Stormwater runoff picks up materials from the Village’s streets, parking lots and yards and is eventually discharged in water bodies used for swimming, fishing and drinking water. Sources of pollution include cars, improper storage of toxic materials, dumping in driveways or streets, fertilizers and pesticides and pet waste.

Wilmette’s NPDES program is designed to meet the following standards set forth by the U.S. EPA:

  • Public education and  outreach
  • Public participation and involvement
  • Construction site runoff control
  • Post-construction runoff control
  • Illicit discharge detection and elimination
  • Municipal pollution prevention and good housekeeping

Program Implementation

As part of the NPDES program, Wilmette has changed its practices on fertilizer and pesticide application and increased environmental controls on construction sites. Wilmette has also teamed up with the Solid Waste Agency of Northern Cook County (SWANCC) and Wilmette School District #39 to educate the public about the importance of water quality. Additionally, Wilmette’s newsletter, The Communicator, regularly contains helpful tips and important information on reducing pollutants in runoff.

If you have questions or concerns, please contact the Public Works Department at 847.853.7500 or

Separate Storm Sewer System (West of Ridge Road)

In Wilmette neighborhoods west of Ridge Road, the stormwater and sanitation pipes are separate. All stormwater runoff in this area is moved to the Village’s pumping facility and then pumped to the North Branch of the Chicago River. This activity is regulated by Wilmette’s National Pollutant Discharge Elimination System (NPDES) Permit for Storm Water Discharges from Separate Storm Sewer Systems (MS4), issued by the Illinois Environmental Protection Agency (IEPA). The Village is required to submit an annual report to the IEPA, summarizing the Village’s implementation of Stormwater Best Management Practices (BMPs) and compliance with the NPDES MS4 Permit.

Village of Wilmette Stormwater Management Program

General NPDES Permit No. ILR40 for Discharges from Small Municipal Separate Storm Sewer Systems (MS4)
Neighborhood Storage Project Phase I - Notice of Coverage under General NPDES Permit No. ILR40
2021 Notice of Intent for Renewal of General NPDES Permit ILR40
Village of Wilmette NPDES MS4 Annual Report: Year 19 (March 2021 - March 2022)
Village of Wilmette NPDES MS4 Annual Report: Year 18 (March 2020 - March 2021)
Village of Wilmette NPDES MS4 Annual Report: Year 17 (March 2019 - March 2020)
Village of Wilmette NPDES MS4 Annual Report: Year 16 (March 2018 - March 2019)
Village of Wilmette NPDES MS4 Annual Report: Year 15 (March 2017 - March 2018)
Village of Wilmette NPDES MS4 Annual Report: Year 14 (March 2016 - March 2017)
Village of Wilmette NPDES MS4 Annual Report: Year 13 (March 2015 - March 2016)
Village of Wilmette NPDES MS4 Annual Report: Year 12 (March 2014 - March 2015)

What can residents do to help?

  • Did you know that pet waste can pollute our local waterways? Proper pet waste management will assist the Village in eliminating pollution or wastewater from entering into the waterway system. Click here for more information. 
  • Don’t wash your car at home. When you wash your car in the driveway, the soap, dirt, oil, and grease from your car flows into nearby storm drains, which can be harmful to animals and degrade water quality.
  • Don’t rake your leaves into the street too early. Fallen leaves contain phosphorous and nitrogen, which can leach into rain water and flow into storm drains. Excess phosphorous and nitrogen can cause algal blooms in local waterways and degrade water quality. If you can, wait until the day before your scheduled leaf collection day to rake your leaves into the street.
  • Steer clear of coal tar! Since 2017, the Village of Wilmette has banned the sale and use of coal tar sealant products for sealcoating pavement surfaces (all public and private driveways, parking lots, and other roadway surfaces, including property owned by the Village and other governmental units). Coal tar contains high levels of polycyclic aromatic hydrocarbons (PAHs), which are a group of organic chemicals that are of environmental concern due to their toxicity. When used in sealcoating products, PAHs can be tracked into your home or leach into stormwater runoff posing a health hazard to humans and wildlife. Property owners can use asphalt-based sealants, which are significantly lower in PAH levels and are commercially available. Please remind your contractor that coal tar products are banned in Wilmette.

Combined Sewer System (East of Ridge Road)

Draft General NPDES Permit No. ILM580012 for Discharges from Combined Sewer Overflows (CSOs)

Combined Sewer Overflow Operational and Maintenance Plan Summary

Pollution Prevention Plan