EPA’s about-face on the impairment status of Iowa drinking water sources ignores grave pollution risks and undermines public trust in agencies charged with safeguarding drinking water.
IOWA—In response to a lawsuit by Food & Water Watch, the Iowa Environmental Council (IEC), and the Environmental Law & Policy Center (ELPC), the U.S. Environmental Protection Agency (EPA) has finalized its decision to, without scientific justification, delist seven impaired waterways from the Iowa Department of Natural Resources’ 2024 303(d) Impaired Waters List. The groups’ lawsuit asks the Court to order EPA to relist the waters, which contain dangerous levels of cancer-linked nitrates.
The public has a vital interest in nitrate concentrations. A recent Iowa Environmental Council and Harkin Institute report found that Iowa has the nation’s worst waterway nitrate contamination. Nitrate, linked to birth defects and cancers, is found in synthetic fertilizers and factory farm waste. Iowa has the fastest rising cancer rate in the nation and the second-highest cancer rate overall.
“While the state reels from a worsening cancer and water pollution crisis, it is clearer than ever that Trump’s EPA is turning its back on Iowa,” said Food & Water Watch Staff Attorney Dani Replogle. “We look forward to judicial scrutiny of EPA’s unjustified position on Iowa’s drinking water sources.”
“The EPA is doubling down on a bad decision that has no basis in science or fact,” says Michael Schmidt, General Counsel for IEC. “These major Iowa waterways are clearly polluted, and increasing evidence links nitrates in drinking water with cancer and other major health concerns. The decision to delist them is reckless and frankly dangerous for the residents of Iowa.”
“Iowans know that we have a water quality crisis. We deserve more than the Trump EPA putting their head in the sand and refusing to act on water quality,” said ELPC Senior Attorney Josh Mandelbaum. “That’s why we will continue our lawsuit to provide accountability to the Trump EPA and to push for action on water quality for Iowans.”
The Impaired Waters list is an inventory of lakes, rivers, streams, and wetlands that do not meet water quality standards set to protect designated uses (such as supporting aquatic life, human recreation, or other specific uses). States must biennially update and submit this list to the EPA. An impairment designation triggers a regulatory process that requires the development of an improvement plan. More than 700 Iowa waterways are currently designated as impaired.
In late 2024, the EPA issued a partial disapproval of Iowa’s impaired waters list, citing the need to include seven polluted waterways — segments of the Cedar, Des Moines, Iowa, Raccoon, and South Skunk rivers, which are designated as drinking water sources and recreational waters for hundreds of thousands of Iowans — due to their contamination with toxic, cancer-linked nitrates exceeding federal safety thresholds. A recent analysis of the Des Moines and Raccoon Rivers found that more than 80% of the rivers’ nitrates stem from industrial agriculture, including factory farms and the intensive row cropping that feeds them.
Then, in a highly unusual reversal outside of normal decision-making processes, the EPA rescinded its prior disapproval and tentatively delisted the seven water segments in July 2025 (see “Timeline” below). This EPA reversal was issued without scientific justification, despite documented evidence that these waterways are contaminated with levels of toxic nitrates that regularly exceed federal safety thresholds.
EPA’s decision to reaffirm the delisting of these Iowa waters includes several major gaps and glaring oversights. For example, EPA ignores available data from the Iowa Water Quality Information System (IQWIS) citing accessibility challenges, despite the data being easily obtainable via request to the University of Iowa. Ironically, EPA also encourages Iowa to conduct more water quality monitoring through IQWIS at the same time the Iowa state legislature continues to defund the water monitoring network.
Timeline
March 14, 2024: Iowa DNR releases draft impaired waters list for comment
April 2024: Iowa Environmental Council and others comment on draft list
May 3, 2024: DNR responds to comments and submits impaired waters list to EPA
November 13, 2024: EPA issues partial disapproval of DNR impaired waters list, saying DNR needs to include nitrate impairments on the Des Moines, Raccoon, Cedar, South Skunk, and Iowa Rivers
December 13, 2024: DNR, IEC, and others comment on the EPA action
December 30, 2024: EPA takes final action to list the waters
May 2, 2025: DNR talks to EPA about the nitrate listings, then emails two documents related to the original adoption of Iowa’s nitrate water quality standard
July 11, 2025: EPA Region 7 sends a letter to DNR rescinding the disapproval from December, removing the nitrate impairments
October 9, 2025: IEC, Environmental Law & Policy Center, and Food & Water Watch send a letter to the EPA) challenging the agency’s action to rescind its partial disapproval of Iowa’s 2024 Impaired Waters list under Clean Water Act section 303(d)
May 15, 2026: IEC, Food & Water Watch, and ELPC sue the EPA over its decision to delist the seven polluted waterway segments
September 29, 2026: EPA confirms its decision to delist the seven waterways
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