The National Pollutant Discharge Elimination System (NPDES) is a program administered by the U.S. Environmental Protection Agency (EPA). The program was created in 1972 by the Clean Water Act to address water pollution by regulating point sources that discharge pollutants to waters of the United States.
KDOT is required to be permitted through the NPDES stormwater program with a Transportation Separate Storm Sewer System (TS4) Permit. The Kansas Department of Health and Environment (KDHE) is responsible for issuing these permits in Kansas.
KDOT's current TS4 permit was issued in February 2024 and expires in December 2028. KDOT’s permit area includes the urban areas of Kansas City, Lawrence, Topeka, Manhattan, Wichita, and St. Joseph, MO, as defined by the most recent U.S. Decennial Census.