Illinois Department of Transportation, Erica Borggren, Acting Secretary
Patrick J. Quinn, Governor
Traveling PublicMapsProjectsRoad ClosuresNewsDoing BusinessLetting & BiddingCareers@IDOTGeneral Info

Storm Water Management Program


In 1972, Congress amended the Clean Water Act to prohibit the discharge of any pollutants into waters of the United States from a point source (e.g. industrial wastewater, municipal sewage, etc.) unless the discharge was authorized by a National Pollutant Discharge Elimination (NPDES) permit. In 1987, the Clean Water Act was further amended to require a comprehensive NPDES program that occurred in two separate phases.

Phase I, which started on November 16, 1990, addressed the most significant sources of pollution in storm water runoff, primarily the municipal storm sewers of medium and larger cities and construction projects that disturbed more than five acres of land. Under this phase, IDOT received a separate permit, ILR10, from the IEPA for each project that met NPDES requirements.

Under Phase II, which began on March 1, 2003, the requirements became more stringent. The threshold to trigger the NPDES permitting process was lowered to one acre of disturbance. Also under Phase II, operators of small municipal separate storm sewer systems or MS4s were required to have authorization to discharge pollutants from construction and maintenance operations as well as their storm sewer systems. These requirements were accomplished through the issuance of the ILR40 permit.

In February of 2009, the IEPA issued a new ILR40 permit. A major change from the old permit is how the Notice of Intent (NOI) for construction projects is handled. Previously, the ILR40 permit covered all of the Department’s activities, including construction projects. Under the new permit, IDOT construction sites are granted automatic coverage under the ILR10 permit 30 days after a Notice of Intent (NOI), individually submitted for each construction project, is received by the IEPA. IDOT will receive a unique ILR10 permit number for each construction project.

However, being an MS4 has additional requirements. Some of these requirements are as follows

  • Storm Water Management Plan (SWMP) - Addresses storm water pollution controls related to highway planning, design, construction, and maintenance.

  • Annual Reports - Discusses success of the Best Management Practices (BMPs) set up to fulfill the requirements of the six minimum control measures described in the permit. The six minimum control measures are as follows:

  1. Public Education and Outreach

  2. Public Involvement

  3. Illicit Discharge and Detection

  4. Storm Water Erosion Control

  5. Post Construction Monitoring

  6. Pollution Prevention – Good Housekeeping

Lastly, IDOT is actively involved in assuring compliance of NPDES requirements for state highway projects. We feel one of the best ways to do this is educating its staff and contractors. This is why we have regularly scheduled classes on NPDES requirements. The Department also works directly with the IEPA in a stormwater committee and regularly meets with those agencies that inspect projects for NPDES compliance.

Related Items

Web Links

Topics & Links

Transportation and
the Community
Cultural Resources
Natural Resources
Geologic and Special Waste
References and Environmental Documents
Green Initiatives
IDOT Privacy Statement | Illinois Privacy Information | Kids Privacy | Web Accessibility  | FOIA