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Storm Water Management Program (SWMP) Plan

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Clean Water Act [33 U.S.C. 1251 et seq. (1972)]

The federal Clean Water Act (CWA) made it unlawful to discharge any pollutant from a point source (such as a pipe from a factory or wastewater treatment plant) into most surface waters (i.e. ponds, lakes, streams, rivers, etc.), unless a permit was obtained. The Illinois Environmental Protection Agency (IEPA) administers the permit process through the National Pollutant Discharge Elimination System (NPDES) program. The Village of Carol Stream discharges to local surface waters under the following two NPDES permits:

  1. NPDES Permit No. IL0026352 (Wastewater): This permit covers discharge from the Carol Stream Water Reclamation Center (aka wastewater treatment plant or sewage treatment plant or sanitary treatment plant). The Village owns and operates over 50 miles of sanitary sewers that convey sewage from residential, commercial, and industrial buildings for treatment before discharging to Klein Creek.
  2. NPDES Permit No. IL4000308 (Storm Water): This permit covers discharge from the Village's separate storm sewer system. The Village owns and maintains over 100 miles of storm sewers that convey storm runoff (aka rainwater) from both private and public property into waterways at over several dozen discharge locations. The permit requirements are defined by General NPDES Permit No. ILR40 for "Discharges from Small Municipal Separate Storm Sewer Systems" (NPDES MS4 Permit).

The following information pertains solely to the second permit noted above (IL4000308), while information regarding the first permit (IL0026352) can be obtained by contacting the Public Works Department. 

Municipal Separate Storm Sewer System (MS4) 

The Village's storm sewers are separate from the sanitary sewers. This means any water they convey discharges directly into surface waters without being treated by the water reclamation center. Therefore, unless minimum control measures are undertaken, any pollutants being carried by these storm sewers make their way into local streams and ponds. 

Storm Water Management Program (SWMP) Plan

The NPDES MS4 Permit requires that the Village develop a SWMP Plan to reduce pollutants by the "maximum extent practicable" using the following six Minimum Control Measures (MCM). This webpage, and all sub-pages, are intended to serve as the Village's Plan.

  1. Public Education and Outreach on Storm Water Impacts
  2. Public Involvement / Participation
  3. Illicit Discharge Detection and Elimination
  4. Construction Site Storm Water Runoff Control
  5. Post-Construction Storm Water Management in New Development and Redevelopment
  6. Pollution Prevention / Good Housekeeping for Municipal Operations

On April 16, 2018 the Village entered into an Intergovernmental Agreement (IGA) with DuPage County (Resolution No. 3010) to operate under a single NPDES MS4 Permit. A similar IGA was also signed by 41 other governmental entities within DuPage County with the intent to eliminate duplicate efforts and paperwork, resulting in a reduction of costs to the taxpayer while maintaining or improving upon the provided level of service. The Illinois Environmental Protection Agency (IEPA) approved the Village's waiver request from it's previous Notice of Intent (NOI) on May 24, 2018 so that the Village is now covered under DuPage County's NOI. DuPage County's responsibilities for each MCM is defined in the IGA and NOI and discussed in further detail within DuPage County's Storm Water Management Program Plan

Local Waterways / Drainage Patterns

The Village drains into two of the three major rivers within DuPage County: the West Branch DuPage River (WBDR) and the East Branch DuPage River (EBDR). Less than 20 acres drain to the EBDR and since none of the Village's storm sewers actually discharge into it, the Village's efforts focus entirely on the WBDR. The Village drains to the WBDR via three tributary streams. Click on the links below for a map that illustrates the areas (i.e. watersheds) that drain to each stream.

  1. Klein Creek
  2. Winfield Creek
  3. Tributary No. 4 to the West Branch DuPage River (Trib. No. 4)

Pollutants of Concern

The IEPA is tasked with assessing whether surface waters are achieving the goals of the CWA. These reports are produced on a biannual basis and are available on IEPA's website. The WBDR, EBDR, Klein Creek and Winfield Creek have all been assessed, while Trib. No. 4 has not. None of the four streams were determined to have the water quality necessary to be achieving the goals of the CWA. While the pollutants of concern varies among the streams, those they have in common are:

  • Trash / Litter / Debris / Garbage
  • Chlorides (Mostly a byproduct of de-icing salt in the winter)


Due to the hypoxia zone in the Gulf of Mexico, the IEPA is also focusing on reducing nutrients such as phosphorous and nitrogen. Phosphorous is more prominent in urbanized areas, which can come from both the wastewater treatment plants and storm water runoff. Since most lawn fertilizers and detergents no longer have significant amounts of phosphorous, it appears that the most significant source of phosphorous from residential areas are from decomposing leaves. Therefore, proper disposal of leaves during 

DuPage River Salt Creek Workgroup

The Village has joined a consortium made up of other wastewater treatment plant agencies and communities to form the DuPage River Salt Creek Workgroup (DRSCW). The DRSCW assists its members by monitoring the water chemistry of local surface waters (NPDES MS4 Permit requirement) and provides technical guidance on ways to reduce pollutants in storm water runoff. In addition, the DRSCW also implements projects based on industry-leading techniques for improving the habitat for aquatic wildlife (such as fish, mussels, insects), whose lack of abundance and diversity are often the main reason why IEPA determines our local waterways are not achieving the goals of the CWA.