Two More Iowa Rivers Are Now Impaired Because Of Nitrates

Iowa's water has been under scrutiny lately, with the recent report that, for the third year in a row, Iowa has the fastest-growing cancer rate in the country.

The Iowa DNR is now seeking public input.  Which, based on a recent social post, is pretty clear.

Integrated Report on Water Quality

The DNR assessed more than 213,000 water-quality results across 61 parameters.  In total, the list shows a net reduction of three impaired segments from the list submitted by DNR in 2024. However, portions of both the Iowa and Raccoon Rivers are now impaired for nitrates.

Nitrate-producing runoff from manure and fertilizer is contaminating Iowa's soil and water supply.  Nitrates can form compounds in the body, which are known carcinogens that damage cells.

The Central Iowa Source Water Resource Assessment Study says 80% of nitrates in Iowa's water supply are from agricultural runoff.

Is This Water Toxic And Unusable?

An impaired waterbody is not unusable. An impairment is used to prioritize resources based on its designated uses or the specific job the water is meant to perform. If one parameter does not meet its intended use, the water segment is impaired. The designated uses are:

• Recreation (Class A): Is this water body safe for swimming?
• Aquatic Life (Class B): Can fish, insects, and other creatures live there safely?
• Drinking Water (Class C): Is this a safe source for drinking water treatment?
• Human Health (Class HH): Are the fish caught safe to eat?

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"The Impaired Waters List is not merely a record of impaired waterbodies; it is a problem-identifying tool and a roadmap for restoration," said Mark Moeller, DNR’s Water Quality Monitoring & Assessment Supervisor. "A waterbody can be listed for failing just one specific parameter, while remaining healthy for other uses like fishing or kayaking."

The full report can be found on the DNR's website, and your comment is welcome through March 19, 2026, and should be sent to: IRcomment@dnr.iowa.gov