Iowa has a population of 3.2 million people, but about 25 million hogs, and regulation of human sewage is much stricter than regulation of animal waste.
That leads to serious concerns over water quality, the subject of a new report presented Wednesday at St. Ambrose University, amidst mounting public pressure to bolster transparency and accountability for Iowa’s worsening water pollution crisis.
On Wednesday night (Nov. 19), Food & Water Watch, St. Ambrose Sustainability Committee, and Progressive Action for the Common Good hosted a panel discussion at the Rogalski Center with three University of Iowa researchers behind the recent Central Iowa Water Quality Report.
The 100-page report was first presented in August at Drake University, attended by 650 people in person and about 800 more people watching live online.
“Even though we'll focus on the Des Moines and Raccoon rivers, and they do have some very unique and interesting characteristics, much of what we'll talk about is relevant to the rivers of Iowa, across Iowa,” said Larry Weber, director of University of Iowa’s Iowa Institute for Hydraulic Research.
Weber shared major findings of the Central Iowa report – commissioned by Polk County, home of Iowa’s capital city, Des Moines – as did Jerry Schnoor of Davenport, University of Iowa Professor Emeritus of Civil and Environmental Engineering, and Elliot Anderson, UI Assistant Research Scientist.
The report’s executive summary says:
“Agricultural production, which is the predominant use of the land in our watersheds, has an overwhelming influence on the rivers. Fertilizer and animal waste move downstream, threatening drinking water sources and increasing the likelihood of harmful algal blooms.
“In urban, suburban, and rural areas, alteration of stream and river ecosystems by channel straightening and bank reinforcement has disconnected waterways from their floodplains. Climate change will exacerbate these issues unless timely and decisive actions are taken to reduce human impacts on the rivers. Our rivers are inextricably tied to our economic vitality, the health of our citizens, and the sustainability of our communities; as such, they need to be our priority.”
The biggest areas of concern for water quality are:
- Livestock Manure Management: Manure generated by agricultural livestock introduces nutrients and chemicals into the environment and must be stored and applied appropriately to ensure it does not contaminate downstream waters. Adequate documentation of its management should be provided to the public by producers.
- Stream Channel Protection: Urban and rural land use has impaired water quality, increased flood risk, and harmed biodiversity through unsustainable development in Iowa’s floodplains. Stream channelization has led to faster, deeper streams and streambank erosion. Land use efforts should incorporate vegetative buffers along waterways and encourage their natural meandering when possible.
- Land Use Adjacent to Rivers: Reductions in impervious surfaces, improvements to soil quality, increases in native plantings, and rain-scaping in urban areas will slow down and filter water. Reductions in the use of fertilizers (including manure) and pesticides, as well as improvements to chemical and waste management, are necessary to protect human and ecosystem health. Protection of floodplains will help reduce flooding and erosion, resulting in protected infrastructure and improved recreation, wildlife habitat, and water quality.
- Harmful Algal Blooms: HABs often produce toxins that harm humans and animals through exposure and threaten drinking water supplies. HABs can also degrade aquatic ecosystems. Due to their unpredictability and numerous health risks, understanding and mitigating the conditions that trigger HABs in rivers and lakes is critical.
The Central Iowa Water Quality Report found that the Raccoon and Des Moines rivers, Central Iowa’s urban drinking water supplies, are dangerously contaminated with cancer-linked nitrates, 80% of which stem from industrial agriculture, including factory farms.
According to Food & Water Watch (a Washington, D.C.-based nonprofit that fights for sustainable food, clean water, and a livable climate), Iowa’s factory farms produce 300 million pounds of manure each day — 25 times more than the state’s human population. This manure (75% of which is generated by hogs) is typically not treated before being dumped into the environment, where it fouls rivers and streams, pollutes drinking water, and fuels climate change.
Food & Water Watch has filed a lawsuit against the EPA to “force them to do their job,” claiming the Trump Administration is allowing millions of pounds of factory farm pollution to be dumped into waterways across the country.
“Food & Water Watch has a history of taking big players to court — and winning,” the group’s website says. “With the help of our members, we’re strengthening regulations on factory farm pollution, stopping dirty energy projects, and helping to bring justice to communities impacted by polluters.”
Risks of nitrates in water
Jerry Schnoor discussed the impact of nitrate concentrations in rivers, which are near the maximum Environmental Protection Agency standard of 10 milligrams or less per liter.
“The Raccoon and the Des Moines rivers that Des Moines has to worry about are even higher, sometimes even higher than eight milligrams per liter averaged throughout the year,” he said, noting roughly 20% of the nitrates come from animal manure.
“There aren't many nitrate treatment systems in the United States because we have this problem in spades,” Schnoor said. “We've really got the problem to a large extent.”
There are potential health risks to nitrates in water, he said, even down to five milligrams per liter, including colorectal cancer, bladder cancer, breast cancer, thyroid diseases, and birth defects.
“But recent health effects studies indicate that maybe the EPA standard should be somewhat lower,” Schnoor said.
Iowa drinking water is routinely contaminated with toxic nitrates in excess of the federal safety threshold, according to the new report. Drinking nitrate contaminated water is linked to a host of negative health outcomes including birth defects and cancers; new evidence suggests that nitrate exposure may be toxic even at lower levels.
Meanwhile, Iowa is the only state in the country with rising cancer rates.
Industrial agriculture is a major source of nitrates and other contaminants. Food & Water Watch analysis finds that Iowa is home to more factory farms producing more waste than any other state — 109 billion pounds annually, more than 25 times the sewage produced by the state’s human population. Iowa farmers also spread more toxic pesticides and chemical fertilizer than any other state.
This summer, nitrate levels in the Raccoon and Des Moines rivers, Central Iowa’s urban drinking water supplies, were in excess of the federal nitrate safety threshold for 33 days. Northeast Iowa’s sensitive driftless area has experienced decades of factory farm nitrate exposure above 10 mg/L; 13 groups have petitioned EPA for emergency action.
“Pesticides are another potential problem, since Iowa has the dubious distinction of being at the center of the corn belt, and that means we're also at the center of the pesticide application rates,” Schnoor noted. One of the most commonly detected pesticides is glyphosate, known as RoundUp.
“Having been from Davenport, you're blessed with Mississippi River water as your drinking water source,” he said. “That's kind of a blessing and a curse in different ways. It's a blessing in that it's much dilution, really, is the solution to pollution to some extent. So your nitrate concentrations are like, on average, two milligrams per liter. They've come up through the years also because of some of the developments that we talked about in this report as well.
“But you have much lower concentrations of many, many contaminants because of the sheer flow, the river flow processes,” he said. “In the Upper Mississippi River basin, which would enter in above Davenport, you, of course, have many of the same risks as the ones that we talked about today, though the concentrations may be lower.”
Improving water quality monitoring
Anderson said there are many local and individual actions that anyone can take to help improve water quality, noted in the report.
“A lot of these revolve around just education or actually going out and participating in collecting water samples, helping researchers with better data, and participating in river cleanup efforts,” he said.
“The second major type of action step that we had was related to watersheds or regional actions. These are things that groups such as Polk County or the watershed management programs that exist around Polk County can take,” Anderson said.
“And then finally, we had a few actions that can be taken at a statewide level. So these would be things that the Iowa government could undertake or different nonprofit groups that operate at larger scales that go from one corner of Iowa to the other,” he said.
The Iowa Water Quality Information System is a University of Iowa program that lost state funding in 2023, and supplemental dollars from the Walton Family Foundation and ISU Nutrient Research Center are expected to run out in 2026.
In August 2025, the Des Moines Water Works Board of Trustees said it opposed the EPA’s move to rescind the impaired-waters designations for the sections of the Raccoon and Des Moines rivers that include its main drinking water intakes.
Nitrates in the two rivers during summer 2025 rose to levels that far exceeded the EPA's own 10 mg/L for processed drinking water. That prompted Central Iowa Water Works, the regional authority of which Des Moines Water Works is the largest member, to issue an unprecedented ban on lawn watering in a bid to maintain enough treatment capacity to ensure sufficient safe water for essential uses, such as drinking, bathing and cooking. The ban has since been lifted.
Polk County is providing $200,000 to keep the monitoring network running, and they’re seeking similar funding from other Iowa counties.
“The most important data we have on water quality comes from monitoring,” Anderson said.
Sensors that monitor nitrate levels in rivers across Iowa are set to go out of service by the summer of 2026, but a fundraising campaign is underway with the hope of extending the lifespan of the project.
The Iowa Water Quality Information System provides a range of daily data, including nitrate levels, in about 75 sites throughout the state.
During a question and answer session, Anderson was asked if any findings in the report relate to eastern Iowa and the Mississippi River.
“So some of the drinking water challenges that we talked about, they're somewhat transferable over here.” Anderson said. “And as we move through this report, I become more and more concerned about the drinking water because those have the most direct influence on human health."
Dennis Tarasi, St. Ambrose associate professor of biology and co-chair of the SAU Sustainability Committee (with faculty, staff and students focusing on improving the school’s environmental efforts), applauded the work of Iowa researchers, adding it’s applicable in the Quad Cities.
“There’s a lot of overlap in the concerns associated with the state of Iowa in general, especially large water bodies,” he said, noting the river going through the heart of Des Moines is similar to the Mississippi in the core of QC downtowns.
“Especially, when you get north of the Quad Cities, the Wapsipinicon is essentially the same sort of river – associated with a lot of agriculture, and concerns associated with runoff and different chemicals,” Tarasi said. “When they start talking about PFAS, that originated in the Quad Cities of the United States.”
In 2023, chemical manufacturer 3M Co. said it would pay $10.3 billion to settle lawsuits over contamination of many U.S. public drinking water systems with potentially harmful compounds used in firefighting foam and a number of consumer products.
That came after the EPA agreed to sample and treat for Polyfluoroalkul (PFAS), also known as "forever chemicals," in drinking water near the Cordova, Illinois facility, and the 3M plant in Camanche, Iowa.
“Clean water is good for everyone,” Tarasi said. “It’s not just an economic benefit; there are health costs associated with missed work and disease burdens, hospitalizations…If people are healthier and able to interact with the water, it’s gonna be better for all of us.”
For more information about the Central Iowa Water Resource Assessment (CISWRA), visit www.polkcountyiowa.gov/public-works/water-resources/polk-county-water-quality-initiatives/.
This story was produced by WVIK, Quad Cities NPR. We rely on financial support from our listeners and readers to provide coverage of the issues that matter to the Quad Cities region and beyond. As someone who values the content created by WVIK's news department, please consider making a financial contribution to support our work.
