Jodi Reese dips a test strip into her tap water and watches it darken. The reading comes back somewhere between five and seven parts per million of nitrates - a chemical from fertilizer and manure that has been seeping into Iowa's groundwater for decades. The legal limit is ten. But the science now says the danger starts closer to three.

Jodi does not drink her tap water. Neither does her husband Terry. Instead, they drive 15 miles to a grocery store to fill five-gallon jugs, which they haul back home to Cass County - the part of Iowa with the highest cancer rates in a state that already has the second-highest cancer rate in the entire country.

Iowa is one of only three states where cancer is still rising. Not plateauing. Rising. And while the national narrative tends to blame individual choices - smoking, drinking, diet - the evidence increasingly points somewhere else: to the industrial farming system that transformed Iowa's landscape over the past four decades, saturated its soil with nitrogen, and piped a slow-moving public health catastrophe directly into people's kitchens.

The Background

Iowa has always been farm country. For most of the 20th century, that meant family farms - mixed operations with a bit of everything: hogs, cattle, chickens, dairy, crops. That model started collapsing in the 1980s, and then in 1998, according to Art Cullen, the editor of the Storm Lake Times Pilot, it was effectively finished. Sow prices were driven to near zero, and independent pork producers were pushed out of the business.

What replaced them were concentrated animal feeding operations, or CAFOs - industrial-scale facilities housing thousands of animals under one roof. Today, a handful of corporate giants dominate Iowa's hog industry. Iowa is the top state in the country for the number of CAFOs.

The scale of this transformation is staggering. A research scientist named Chris Jones has estimated that the hogs raised in Iowa produce as much waste as 125 million people - roughly a third of the entire US population. Iowa itself has 3.2 million residents. That waste, which is high in nitrates - a form of nitrogen that acts as a fertilizer - gets spread across farm fields. Because half of Iowa's farmland grows corn, which is the crop that needs the most fertilizer of any grown in the state, the fields absorb enormous quantities. Both the manure from CAFOs and synthetic nitrogen fertilizer go into the same soil.

The problem is that the nitrates do not stay there. They drain into rivers. They seep into groundwater. They travel through drainage ditches - which Art Cullen bluntly calls what they are - until they reach the taps of Iowa's cities and rural homes.

The EPA set the legal limit for nitrates in drinking water at ten parts per million in 1974. That standard was designed to protect infants from blue baby syndrome, a condition where nitrate exposure impairs blood oxygen levels in babies. It was never meant to be a comprehensive cancer safety threshold. And it has not changed since.

What Is Actually Happening

The science has changed, even if the regulation has not.

A March 2026 report from the Iowa Environmental Council and the Harkin Institute found that 13 of 16 cancer types linked to pesticides, nitrates, PFAS, and radon already occur in Iowa at higher rates than the national average. Of the cancers linked specifically to these pollutants, 11 of 15 are increasing in the total Iowa population. For people under 50, six of ten such cancers are on the rise. The report examined peer-reviewed studies from 2016 through 2024 and found patterns of increased cancer risk at nitrate concentrations well below the current EPA limit of ten milligrams per liter - down to around three.

That threshold matters because approximately one million Iowans are currently drinking water with nitrate levels that, by the new science, are not safe - even if they are technically legal.

The Des Moines and Raccoon rivers rank in the top one percent of all rivers in the United States for nitrate concentration. According to the Iowa Environmental Council report, 80 percent of that contamination comes from agricultural sources, specifically the fertilizer runoff and manure from Iowa's industrial farming system.

Des Moines Water Works - the utility that supplies drinking water to central Iowa - has been running its nitrate removal facility since January 2026. It is the first time the system has had to operate in January in more than a decade. Last summer, the utility ran the facility for 112 days straight, and at one point issued a lawn watering ban to keep demand low enough that it could stay within legal limits.

In May 2026, environmental groups sued the Trump administration's EPA after the federal agency found dangerous nitrate contamination in Iowa's major urban drinking water sources - and then took no action.

A Yale study, published around the same time as the Iowa Environmental Council report, found that people living near CAFOs in California, Texas, and Iowa had higher rates of cancer, suggesting that proximity to livestock operations specifically - not just nitrates in tap water - may be contributing to the pattern.

The Money Trail

Follow the money and you find the reason nothing has changed.

In 2015, Des Moines Water Works sued three northwest Iowa counties over nitrate pollution of the Raccoon River. The utility was spending $10,000 per day to treat the city's water, and wanted mandatory regulations on the agricultural runoff flowing into it. The counties fought back - and they did not fight alone.

The Agribusiness Association of Iowa, the Iowa Farm Bureau, Koch Enterprises, Monsanto (now Bayer), and various seed, chemical, and fertilizer industry groups spent roughly $1 million helping the counties defeat that lawsuit. No new regulations followed.

The Farm Bureau then helped design Iowa's response to the nitrate crisis: a voluntary nutrient reduction strategy - a program that encourages farmers to use less fertilizer but carries no penalties for those who do not. Matt Bormann, a corn and soy farmer north of Des Moines, describes being used by the Farm Bureau as a showpiece in YouTube videos while his neighbors made no changes. "There's nobody else in the area doing this," he said.

The Farm Bureau spent $1.8 million on lobbying against regulations over the past decade. That investment buys something specific. When Chris Jones - then a research scientist at the University of Iowa - started writing publicly about water quality data on a university-hosted blog, people in the legislature began complaining to his bosses. There were implicit threats about funding. In 2023, Republican lawmakers cut $500,000 from the program that funded Iowa's network of real-time nitrate sensors, effectively shutting the monitoring system down. The state senator who led that effort, Dan Zumbach, received $18,500 from the Farm Bureau in 2024.

When the data becomes inconvenient, the answer is to eliminate the data.

This is the shape of the system. Corporate agribusiness funds political campaigns. The politicians it funds design voluntary programs that require nothing and change nothing. Scientists who publish inconvenient findings face retaliation. Water monitoring gets defunded. And one million people drink water that the current science says is dangerous.

What People Are Doing About It

The residents of Cass County are not waiting. Jodi and Terry Reese founded the Nishnabotna Water Defenders after a fertilizer spill sent 265,000 gallons of nitrogen into their local river, killing 800,000 fish across 50 miles of waterway. When the case sat on the Iowa Attorney General's desk for a year with no response, they started testing the water themselves - in rivers, in drainage ditches, and eventually in their own home.

Some farmers are changing their practices without being compelled to. Matt Bormann plants cover crops and grass strips in his fields to absorb nitrates before they drain into rivers. He pushed for the same approach through the Iowa Farm Bureau for years. He has since grown frustrated watching voluntary conservation remain exactly that - voluntary - while the data shows it is not working.

Chris Jones, who ran the state's nitrate sensor network before it was defunded, has now launched a campaign for Iowa's Secretary of Agriculture against the incumbent Mike Naig, a former Monsanto lobbyist. His platform calls for mandatory regulations on CAFOs, a more diversified agricultural landscape, and a shift away from the corn-soy-ethanol monoculture that drives Iowa's nitrate problem. "What we've tried over the past 30 to 40 years has not worked," Jones said. "So let's try something different."

The issue has moved to the center of Iowa politics in a way it never has before, with candidates for both governor and secretary of agriculture now making water quality and cancer rates a central campaign theme. Rob Sand, the Democratic candidate for governor, has proposed aggressive water quality and public health initiatives. The state's primary election was held on June 2, 2026.

Outside the state, a coalition of more than 25 groups called on the Department of Health and Human Services and the EPA to declare a public health emergency over nitrate contamination. The lawsuit against the EPA, filed in May, is still pending.

Iowa, despite being the farm capital of the United States, imports 95 percent of its food. The land that could grow anything grows corn - to feed hogs and produce ethanol. The water that runs beneath it is laced with the chemical consequence of that choice.

The Bottom Line

Iowa's cancer crisis is not a mystery and it is not an accident. It is the predictable result of a system where corporate agribusiness consolidated an entire state's agriculture, saturated its water supply with agricultural chemicals, funded the politicians who blocked regulation, and defunded the scientists who measured the damage. The voluntary conservation programs that replaced mandatory rules have not worked. The science now says the legal limit for nitrates in drinking water is not protective of human health. One million Iowans are drinking water above even that standard. The question is not what caused this. The question is whether the political will to fix it has finally arrived.

Timeline

  • 1974 - The EPA sets the legal limit for nitrates in drinking water at ten parts per million, designed to protect infants from blue baby syndrome. The limit has not changed since.
  • 1982 - 2012 - Iowa's hog inventories grow steadily while other major pork-producing states plateau or decline, driven by the rise of concentrated animal feeding operations (CAFOs).
  • 1998 - Corporate pressure drives sow prices to near zero, pushing independent pork producers out of the Iowa market. Corporate giants consolidate control of the state's hog industry.
  • 2015 - Des Moines Water Works sues three northwest Iowa counties over nitrate pollution in the Raccoon River. Agribusiness groups including Koch Enterprises, Monsanto, and the Farm Bureau spend roughly $1 million helping the counties fight the lawsuit. The lawsuit fails to produce new regulations.
  • 2016 - Chris Jones begins writing publicly about Iowa water quality data while overseeing the state's network of real-time nitrate sensors at the University of Iowa.
  • 2017 - A feedlot project upstream from Bloody Run Creek illegally discharges stormwater during construction.
  • 2023 - Republican lawmakers cut $500,000 from the program funding Iowa's nitrate sensor network, effectively shutting it down. Senator Dan Zumbach, who co-sponsored the legislation, later receives $18,500 from the Farm Bureau in 2024.
  • December 2025 - Food and Water Watch releases an Iowa Blueprint for Clean Water, calling Iowa's nitrate contamination the worst in the nation and proposing 20 policy solutions.
  • January 2026 - Des Moines Water Works runs its nitrate removal facility in January for the first time in more than a decade. Chris Jones launches his campaign for Iowa Secretary of Agriculture.
  • March 2026 - The Iowa Environmental Council and Harkin Institute release an 88-page report linking nitrates, pesticides, PFAS, and radon to Iowa's cancer crisis. Iowa confirmed as having the second-highest cancer rate in the US and one of only three states where cancer is still rising.
  • May 2026 - Environmental groups sue the Trump administration's EPA for failing to act on nitrate contamination in Iowa's drinking water.
  • June 1, 2026 - The New Lede reports that for the first time, Iowa's cancer and water pollution crisis has become a central issue in the state's elections.
  • June 2, 2026 - Iowa holds its primary election. The race for Secretary of Agriculture - between Chris Jones and incumbent Monsanto lobbyist Mike Naig - becomes a referendum on whether the state will change course.

Summary

Who: Iowa residents, corporate agribusiness (including Koch Enterprises and Bayer/Monsanto), the Iowa Farm Bureau, state legislators, and water scientist Chris Jones.

What: Iowa has the second-highest cancer rate in the United States, and it is still rising. Nitrates from industrial hog farming and fertilizer runoff have contaminated the state's drinking water at levels the current science links to multiple cancers. Voluntary conservation programs have failed to reduce contamination. Politicians funded by agribusiness have blocked mandatory regulations and defunded water monitoring.

When: The corporate consolidation of Iowa's hog industry accelerated from the 1980s onward. The legal consequences began with the 2015 Des Moines Water Works lawsuit. The public health reckoning has been building through 2025 and 2026, with a major scientific report in March 2026, a federal lawsuit in May 2026, and Iowa's primary election on June 2, 2026.

Where: Iowa, primarily its northwest and north-central counties where CAFO density is highest. The Raccoon and Des Moines rivers are the most contaminated, but the problem extends statewide. Cass County has the highest cancer rates within the state.

Why: Concentrated animal feeding operations produce waste equivalent to 125 million people in a state of 3.2 million. That waste, along with synthetic fertilizer applied to corn fields, drains nitrates into Iowa's rivers and groundwater. The EPA's legal safety limit for nitrates dates to 1974 and has never been updated to reflect modern cancer research. Agribusiness interests have spent millions blocking regulatory changes, and state politicians have complied.