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.

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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. Within 30 days of this action, EPA will identify waters to be added to Minnesota’s list due to exceedances of the state’s sulfate criterion, and will then open a 30-day public comment period on the addition of wild rice waters to Minnesota’s CWA Section 303(d) List. After considering public comments received and potentially making revisions to the waters identified in its disapproval, EPA will send the list of waters to Minnesota for use in developing TMDLs.

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.

Public comments

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

PDF icon Public comments on Minnesota's 2020 Impaired Waters List (wq-iw1-65f)

PDF icon Responses to public comments received on the 2020 Draft Impaired Waters List (wq-iw1-65ga)

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.