Iowa Lists Over 700 Impaired Water Bodies in New Report

State DNR releases draft 2026 biennial report on water quality issues

Published on Feb. 21, 2026

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The Iowa Department of Natural Resources has released a draft version of its 2026 biennial integrated report, which lists more than 700 segments of rivers, lakes, or wetlands in the state as impaired. The list includes well-known bodies of water like the Boyer River, Carter Lake, and the East and Middle Nodaway Rivers. The impaired list is based on water quality data from 2022-2024 for rivers and streams, and 2020-2024 for lakes, and determines if a water segment meets designated criteria for uses like fishing, recreation, or drinking water.

Why it matters

The impaired listing triggers a restoration process under the federal Clean Water Act, requiring the state to develop plans to improve water quality in these segments. While the overall number of impaired waters has remained relatively stable since 2014, the new report adds two river segments impaired for high nitrate levels, an ongoing water quality issue in Iowa.

The details

The draft 2026 report lists 3 fewer impaired segments than the 2024 report, but does not include 7 segments that the EPA had attempted to add in late 2024 due to nitrate impairment. The state challenged those additions, and they were ultimately removed by the EPA over the summer. The new report lists two segments of the Iowa River and Raccoon River as impaired for nitrates, though the state says its assessment criteria for nitrates did not change from the previous report.

  • The draft 2026 biennial report was released on February 18, 2026.
  • The public comment period on the draft report is open for 30 days.
  • The final report will be submitted to the EPA after the public comment period.

The players

Iowa Department of Natural Resources

The state agency responsible for managing Iowa's natural resources, including water quality monitoring and reporting.

U.S. Environmental Protection Agency

The federal agency that oversees implementation of the Clean Water Act, including reviewing state water quality reports.

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What they’re saying

“The number of impaired segments have been 'relatively stable' from 2014 to 2024.”

— Iowa Department of Natural Resources (kjan.com)

What’s next

The final 2026 biennial report will be submitted to the EPA after the 30-day public comment period closes.

The takeaway

This report highlights the ongoing challenges Iowa faces in maintaining water quality, with over 700 bodies of water still listed as impaired. While progress has been made, the state must continue working to address issues like nutrient pollution that are contributing to these impairments under the Clean Water Act.