As required by the federal Clean Water Act, the MPCA assesses all waters of the state and creates a list of impaired waters every two years. This list includes waters that fail to meet water quality standards and uphold that water body’s designated use.
Your dollars at work
Funding for this initiative comes from the Clean Water Fund, part of the Clean Water, Land and Legacy Amendment that Minnesotans approved in 2008. The MPCA uses Clean Water Fund dollars to protect, enhance, and restore water quality in lakes, rivers, streams, and groundwater.
The listings are based on intensive water quality monitoring of major lakes and streams in Minnesota’s 80 watersheds, along with data from partners. This list is used to set pollutant-reduction goals needed to restore impaired waters, called the total maximum daily load (TMDL).
Public comment period open through July 22
Help ensure MPCA assessments are accurate by providing comments on the draft Impaired Waters List, Statewide mercury TMDL list, and assessment manual (which includes the identified list of wild rice waters).
While the entirety of these documents are open for comment, MPCA particularly requests comments on areas that have changed since the last public notice of the Impaired Waters List:
- updates to the Impaired Waters List: new 2026 impairments (indicated by “Year added to List”) delistings, changes, and corrections (each with their own section of the list)
- updates to the Guidance Manual Appendix H regarding identification of wild rice waters
The MPCA invites written comments on the draft documents listed from Tuesday, May 19, 2026, through Wednesday, July 22, 2026, at 11:59 p.m. MPCA will respond to comments submitted online.
MPCA will make edits to these documents based on comments received during the public comment period. MPCA will submit the draft IWL, along with comments and responses, to the U.S. Environmental Protection Agency (EPA) for final approval.
Defining impaired waters
A body of water is considered “impaired” if it fails to meet one or more water quality standards. Minnesota water quality standards protect lakes, rivers, streams, and wetlands by defining how much of a pollutant can be in the water before it is no longer drinkable, swimmable, fishable, or useable in other, designated ways (called “beneficial uses”). It is important to note that a water impaired for one designated use does not mean it cannot be used for other designated uses.
Impairments include:
- mercury levels that lead to limits on fish consumption
- nutrients that grow algae
- sediment that clouds water
- bacteria that can make water unsafe for swimming
- unhealthy conditions for fish and bugs
- PFOS found in fish tissue
- sulfate impairments that may hinder the biological production of wild rice
The MPCA works with many partners to identify the sources of pollutants and stressors to aquatic life, and determine reductions in pollutants and other changes needed to restore waters to meet water quality standards.
Other information
Document sharing site including maps and supporting information on newly included wild rice waters.
MPCA uses this biennial narrative report to meet some of the reporting requirements under the federal Clean Water Act.
Minnesota’s 2024 Impaired Waters List:
- Approved by U.S. EPA - April 2024