The U.S. Environmental Protection Agency (EPA) added seven water segments to Iowa’s list of impaired waters for 2024, including parts of the Cedar River, after rejecting part of the state assessment. The EPA now wants to hear the public’s opinion on its decision.

Under the Clean Water Act, a water segment refers to a defined section of surface water that is monitored for pollution levels. States must evaluate these segments every two years and submit a list of those that do not meet water quality standards.

This year, the Iowa Department of Natural Resources (DNR) identified more than 700 water segments as impaired, but the EPA said Iowa’s list “partially meets” the law’s requirements , according to a letter from the agency.

Impaired waters are those where pollution levels exceed safe limits, requiring a water improvement plan called a total maximum daily load (TMDL).

The EPA added segments of the Cedar, Des Moines, Iowa, Raccoon and South Skunk rivers to the list because of high levels of nitrates and nitrites, which are harmful to the environment and drinking water. The Cedar River, which runs through eastern Iowa, is particularly affected by this decision.

The EPA has criticized Iowa for failing to adequately address concerns about nitrogen pollution. The agency’s letter says the state has not revised its assessment of nitrate and nitrite contamination, despite previous requests. The Iowa DNR, however, disagreed with the EPA’s position, stating in a May 2024 response that it would not change its methodology because EPA had not provided new scientific evidence to support a policy change.

With the addition of these seven segments, the 2024 list now includes 712 degraded water bodies.

The EPA also approved the removal of 84 segments that now meet water quality standards.

The EPA is accepting public comments on its decision until December 13. Information on how to submit comments is available on the EPA website.