Minnesota’s Impaired Waters List

Every two years, MPCA creates a list of impaired waters that do not meet water quality standards. Learn more: Defining impaired waters.

Stay informed. Have questions or need assistance? Sign up for updates or contact Miranda Nichols, 651-757-2614 or 800-657-3864 toll free.

2020 Impaired Waters List

On March 26, 2021, EPA partially approved and partially disapproved Minnesota’s 2020 Clean Water Act (CWA) 303(d) list of impaired waters that require establishment of a total maximum daily load (TMDL) to attain water quality standards. EPA approved the list of waters identified by Minnesota as consistent with Section 303(d) of the CWA and EPA’s implementing regulations. EPA disapproved Minnesota’s decision not to list any waters as impaired due to exceedances of the State’s sulfate criterion to protect wild rice because existing and readily available data and information indicate impairments of that criterion.

EPA is seeking comments on its identification of three water quality limited segments (WQLSs) impaired due to sulfate for inclusion on Minnesota’s 2020 List of Impaired Waters under Section 303(d) of the Clean Water Act (CWA). Comments received by EPA in response to the 60-day public comment period for EPA’s previous additions to Minnesota’s 2020 List of Impaired Waters (4/29/21 to 6/30/21) supported the identification of three additional waters: Perch Lake (WID 69-0688-00), Sturgeon Lake (WID 25-0017-01) and a St. Louis River estuary segment (WID 69-1291-04). Comments must be submitted by October 1, 2021. After considering public comments and making appropriate revisions, EPA will transmit the final list to Minnesota. For details on the three WQLSs and how to comment go to EPA’s website.

PDF icon EPA letter: Addition of Waters to Minnesota’s 2020 List of Impaired Waters under Clear Water Act, Section 303(d) (wq-iw1-65j)

PDF icon EPA Wild Rice waters map and list (wq-iw1-65k)

PDF icon US EPA's decision document on Minnesota 2020 Impaired Waters List (wq-iw1-65i)

File 2020 Impaired Waters List (wq-iw1-65)
  • 2020 TMDL list (303(d))
  • 2020 Inventory of all impaired waters
  • Delisted waters
  • Appendix A of the Statewide Mercury TMDL

PDF icon 2020 Guidance manual for assessing the quality of Minnesota surface waters for determination of impairment: 305(b) Report and 303(d) List (wq-iw1-04k)

Describes Minnesota's monitoring and assessment strategy, assessment tools, and the redesigned assessment process. The purpose of this guidance is to define the required data and information and lay out the criteria by which waterbodies are assessed to determine if beneficial uses are supported.

Impaired lakes include Little Sandy, Swan, East Vermillion, Embarrass, Wynn, Cedar Island, Esquagama, and Mongolia. Impaired rivers include Clearwater, Pike, Long Prairie and Crow River. See the EPA Wild Rice waters map and list PDF for the full list.

Public comments

The comment period for the 2020 Impaired Waters List and assessment guidance manual was open Nov. 12, 2019, through Jan. 14, 2020.

See the Impaired Waters Viewer (IWAV) for all impaired waters, including those just listed, delisted, and corrected for the new list.

Other information

PDF icon 2020 Minnesota Water Quality - Narrative report to Congress (wq-s7-52)

Also known as the 305(b) Integrated Report, combines two requirements of the Clean Water Act to report to Congress on the quality of Minnesota's waters.

For GIS professionals: Go to MPCA's spatial data webpage to download shapefiles on Minnesota's impaired waters.