Iowa Has the Second-Highest Cancer Rate in the Country. The Water Has Something to Do With It.

Iowa is one of only a handful of states where cancer rates aren't falling. They're climbing. The latest annual report from the Iowa Cancer Registry shows the state has the second-highest rate of cancer in the country and is one of only a few states where cancer rates are on the rise. Researchers, public health officials, and now politicians are all pointing to the same question: what's in the water?

The answer is not simple, but the leading culprits are not hard to identify. Nitrates, PFAS, pesticides, and other agricultural and industrial contaminants have been showing up in Iowa's drinking water for decades. And the science connecting those contaminants to cancer is getting harder to dismiss.

The Nitrate Problem Is Bigger Than People Realize

Iowa's agricultural dominance is a point of pride for the state and the source of one of its biggest public health challenges. When nitrogen fertilizers are applied to farmland, rain carries them through drainage tiles and into rivers and groundwater. Those rivers and groundwater sources eventually become someone's drinking water.

The EPA's legal limit for nitrates in public drinking water is 10 milligrams per liter. That standard was set to protect infants from a condition called methemoglobinemia, also known as blue baby syndrome. It was never designed with long-term cancer risk in mind.

That's a problem. Jason Semprini, PhD, MPP, assistant professor of public health at Des Moines University, has studied how prenatal nitrate exposure, even at levels below the safe regulatory threshold of 10 milligrams per liter, does not appear to be without risk to pregnant mothers. And that's before you get to cancer.

Des Moines Water Works has a long history of treating nitrates in its water supply in the Des Moines and Raccoon Rivers. For the past two summers, nitrate readings in the rivers have spiked above the EPA's limit, reaching some of their highest levels in over a decade. Things got bad enough that Central Iowa Water Works issued lawn watering bans just so treatment facilities could keep up. That is not a sign of a system under control. 

A report from the Iowa Department of Natural Resources showed Iowa had 36 nitrate-related drinking water violations in 2025, which is more than double the number reported in 2024.

PFAS and Pesticides Are in the Mix Too

Nitrates are the loudest part of the conversation right now, but they're not the only contaminant fueling Iowa's cancer crisis. The Iowa Environmental Council released a report earlier this year, developed in collaboration with the Harkin Institute at Drake University and based on analysis of more than 250 studies, that identified four major environmental risk factors for Iowa's elevated cancer rates: nitrates, PFAS, pesticides, and radon.

PFAS, the class of synthetic chemicals often called forever chemicals, enter waterways through wastewater streams and industrial discharge. They accumulate in the body over time and have been linked to multiple cancer types. PFAS can reach people through non-stick cookware, certain types of clothing, cosmetics, and other products, but drinking water is one of the most direct and consistent exposure routes. 

The Iowa Environmental Council has been taking its report on the road, holding community conversations across the state in counties where cancer rates are highest. At a recent session in Boone County, a county with both a cancer incidence rate and a cancer mortality rate above state and national averages, Kerri Johannsen, the council's senior director of policy and programs, asked the room a simple question: raise your hand if you know someone who has had cancer. Every hand went up. 

Voluntary Measures Haven't Worked

Iowa created the Iowa Nutrient Reduction Strategy more than a decade ago as a voluntary plan aimed at reducing nitrogen and phosphorus runoff on farms. Adoption has lagged behind the level researchers say is needed to significantly reduce nitrate pollution. While nitrogen levels were up and down during that time, there was no significant change. 

Semprini's research found that the only effective long-term solution is to address the source, reducing the amount of fertilizer and runoff through different types of protective agricultural practices. In Iowa, these measures are mostly voluntary and not likely to change farming practices at the scale needed. 

David Cwiertny, who directs the University of Iowa's Center for Health Effects of Environmental Contamination, has noted that the EPA acknowledges the science on nitrate health risks needs further evaluation to determine whether the current standard is sufficiently protective of public health, and that this leaves water providers and consumers in Iowa in a very difficult position. Standards that haven't been updated in decades are doing the job of protecting people from contaminants that science has continued to study for decades.

People Are Taking Matters Into Their Own Hands

In the absence of meaningful policy action, Iowans are doing what they can at the household level. At community forums around the state, attendees have talked openly about installing home filtration systems, testing their private wells, and changing what they consume. At the Boone County event, one attendee said she installed a reverse osmosis system in her home to help limit her exposure to potential toxins in the water. She's not alone. Iowa Public Radio has reported that public health experts point to reverse osmosis as one of the most effective tools available to individual households dealing with elevated nitrates and other contaminants.

That's exactly what Sanavia was built to address. A whole-home reverse osmosis system removes up to 99% of contaminants, including nitrates, PFAS, heavy metals, and pesticide residues, before the water ever reaches your glass, your ice maker, or your cooking pot. It's not a policy solution. It's a practical one, available right now, for families who don't want to wait.

The Bottom Line

Iowa's water crisis did not happen overnight. It has been building for decades as fertilizer application increased, regulatory standards stagnated, and voluntary conservation programs failed to gain real traction. The result is a state with some of the most contaminated drinking water in the country and a cancer rate that keeps climbing.

The policy debate needs to happen, and it needs to move faster. Farmers, regulators, utility operators, and elected officials all have a role to play. The families drinking this water every day can't afford to wait.

If you live in Iowa, or anywhere with high agricultural runoff, known PFAS contamination, or aging water infrastructure, the smartest thing you can do right now is test your water and filter it. You deserve to know what's coming out of your tap.

 

 

References:

Masters, C. (2026, July 27). High cancer rates and dirty water: The crisis shaping Iowa's toss-up governor's race. NPR. https://www.npr.org/2026/07/27/nx-s1-5900895/water-cancer-iowa-governor-midterms-democrats-sand-maha-lahn

Gifford, J. (2026, February 25). When water turns toxic. Des Moines University. https://www.dmu.edu/blog/2026/02/when-water-turns-toxic/

Koons, C. (2026, July 28). Report on reducing environmental risks of cancer travels across the state. Iowa Capital Dispatch. https://iowacapitaldispatch.com/2026/07/28/report-on-reducing-environmental-risks-of-cancer-travels-across-the-state/