THOUGH ONLY a five-minute drive from the city center, Des Moines Water Works feels a world away from the bustle and sprawl of Iowa's largest city. Surrounded by verdant woods, the utility's main campus sits beside the Raccoon River, which snakes through nearly two and a half square miles of parkland to meet the Des Moines River on the south side of the city. Together, the rivers supply drinking water to over half a million people in and around Des Moines.

I visited Water Works in June 2021 at the peak of a two-week heat wave. The chief executive officer, Ted Corrigan, and external affairs manager Jennifer Terry met me near the entrance of the facility. Both were polite if a bit distracted. The withering heat had them on edge—not because the temperature made them uncomfortable but because of its effect on the city's water supply. We began our tour in a fluorescent lab, where a researcher pointed to a sample of water taken that morning from the Raccoon River. It was dusky green, sludgy, and clouded.

A sign warns of poor water quality at Big Creek State Park in Polk City.

Owing to a dry year, water levels in the Raccoon River were at 10 percent of their normal volume. Meanwhile, the Des Moines River was having its own problems. Corrigan and Terry were waiting for the results of a test that would determine whether the river water was contaminated with microcystin, a dangerous algae-born toxin. Water Works was running the test three times a day, and the staff's nerves were worn thin. If high levels were detected, they would have to depend solely on the dangerously low Racoon River. In the worst-case scenario of both rivers testing positive for microcystin, they would have to ramp up production at two other treatment plants, resort to their limited supply of groundwater, or rely on enhanced treatments to the river water and pray that contaminated water hadn't already made it to taps.

For decades, water supplies in agricultural regions, which are routinely contaminated by large amounts of fertilizer and manure, have been plagued with algae blooms and the presence of other harmful organisms. For nearly three days in August 2014, Toledo, Ohio, ordered a full tap shutoff because of toxins produced by algae. In 1993, Milwaukee's water supply was contaminated by the parasite cryptosporidium, sickening 400,000 and killing 69. "This is serious business," Terry told me, drawing her glasses down her nose to look at me. "It's not 'will there be another Toledo?' It's 'when?' And we don't want it to be us."

Algal blooms are hardly the only pollutant Des Moines Water Works must handle. High levels of nitrate, a nitrogen compound that is harmful to human health, have become a problem nearly year-round. In early spring, levels in the water supply begin to spike when the snowpack thaws out and manure and fertilizer in the soil run into the rivers, helped along by spring rains. This coincides with planting season, which deposits even more nitrogen into the soil. In the fall, when the algae blooms die off, nitrate levels rise again (algae consume nitrates).

A Des Moines native, Corrigan has worked at the utility for 31 years. Volatility has always been part of the job. "The thing that struck me when I came here was, wow, the quality of the source water changes like hourly," he told me. "You gotta be on your toes, because there are so many potential challenges, and they're coming at you on a daily basis."

When nitrate levels get too high, and there are no other feasible water sources, Water Works runs state-of-the-art nitrate-removal equipment at a cost of $10,000 per day. In 2015, 177 days of removal cost $1.4 million. But the system is overburdened by a cascade of contaminants, and Water Works is scrambling to shore up its response, spending $30 million to build new wells that draw shallower, safer groundwater, expanding capacity for winter storage, and beefing up treatment capacity in new plants. "We're trying to stay ahead of it," Corrigan said, "but every time we turn around, there's a new wrinkle, something else we have to build our way out of or deal with."

New investments are already becoming obsolete. "Our drought source, Saylorville Reservoir, which we paid millions of dollars to have upsized, is now contaminated with microcystin every time we have a drought, and we can't use it," Corrigan said. "That's an enormous frustration to us."

Algae covers the surface of the Lake of Three Fires in Bedford

Along with algal blooms and nitrate loads, a complicated stew of chemicals used by the state's agriculture industry is making its way into water sources, with little understanding yet of the chemicals' full effects on public health. Meanwhile, climate change is bringing more extreme fluctuations between rain and drought. Warmer, wetter weather is more hospitable to algae. Drought and flooding, which are happening more often and with more intensity, operate as a vicious one-two punch: Drought concentrates nitrogen in soil, and heavy rains flush contaminants into waterways.

The weekend after my tour, rain finally arrived, easing the water shortage. For the staff at Des Moines Water Works, the reprieve was temporary. Drought conditions persisted into the fall, and experts feared the result would be nitrate levels of historic proportions come spring. In the face of ever increasing, myriad threats, there's only so much that a beleaguered water utility can do. Sooner or later, Iowans will have to reckon with the fact that if they want clean drinking water, they're going to have to tackle the pollution at its source.

IT'S HARD TO IMAGINE the Iowa landscape as it existed only 150 years ago. The native ecology of the prairie was a dynamic, incessant conversation among high grasslands, river floodplains, and the woodland savannas that mediated the two. Vast wetlands served as an intercontinental outpost for avian migration. It all amounted to one of the most diverse, abundant, and complex ecosystems in North America.

Beginning in 1804, American settlers used war, deception, and broken agreements to decimate and exile Iowa's Native communities—the largest group was known as the Ioway—to Kansas and Nebraska. By the 1860s, the young state was dominated by white colonizers, who drained, cleared, and excavated the land for its rich topsoil. To make the soil suitable for row cropping, farmers constructed drainage tiles—essentially underground pipes—to dry out fields, creating a direct conduit into waterways and accelerating their erosion.

Since his children were born with birth defects, Seth Watkins has changed his farming practices to prioritize water protection.

After World War II, synthetic fertilizers became widely available and affordable, and farmers began liberally applying them to their fields. Excess phosphorus and nitrogen seeped into groundwater and flowed through the drainage pipes into streams, setting in motion the disruption of the largest watershed in North America.

In 1945, a doctor in Iowa City noticed two cases of then-novel "blue baby syndrome," a condition suffered by infants that can be fatal. Researchers eventually tied the syndrome, which was occurring at elevated rates throughout the Midwest, to infant formula mixed with well water that was contaminated with high levels of nitrates. Once the cause was determined, cases gradually declined, but the episode served as an early warning about the potential health effects of nutrient pollution.

In 1974, the EPA set a standard for nitrate concentration in drinking water at 10 milligrams per liter. Nearly two decades later, Des Moines Water Works constructed the most expensive nitrate-removal facility in the world (at the time) to meet that standard. Since then, increasing evidence has pointed to serious health issues related to nitrate levels far lower than the EPA standard. Levels below 10 mg/l have been shown to lower blood oxygen in adults and increase the risk of miscarriages, low birthweight, preterm birth, and birth defects. Numerous cancers have also been linked to low levels of nitrate exposure.

If the EPA adopted a 5 mg/l drinking water standard for nitrate, public water utilities across Iowa would have to invest in nitrate removal, an unmanageable expense for all but Des Moines. Most of Iowa's other cities don't have facilities equipped to do it, and in a typical town, the investment would practically double the cost of water treatment. Private wells, the predominant water source in agricultural areas, have the highest nitrate concentrations in the state. But, except for a handful of local health boards, no government authority performs monitoring of any kind.

Nitrate pollution in Iowa's drinking water has been well documented for decades, but rather than respond meaningfully to the crisis, present-day agricultural practices in Iowa have exacerbated it. The state's massive farm sector produces millions of acres of row crops, mostly corn and soybeans. Because fertilizer is cheap, farmers tend to use more than necessary—on average, 30 pounds per acre more than Iowa State University says is optimal for maximum yield, or about 15 percent extra. There are no state or federal regulations stipulating how much synthetic fertilizer farmers can apply to their soil.

The state also raises millions of hogs, turkeys, chickens, and cattle in prefab metal sheds or open-air feedlots that pepper the countryside by the thousands. Manure—equivalent in volume to the excrement of 134 million humans—collects in pits and lagoons that have to be emptied regularly, often by spreading the waste on nearby cropland. It inevitably makes its way into the watershed, where it contributes to high nitrate levels along with pathogen contamination. Farmers have used manure as fertilizer for thousands of years, but with concentrated livestock populations, the sheer volume of waste overwhelms ecosystems. Widespread mismanagement—including spreading manure on frozen ground, where it sits until spring rains wash it into the nearest stream—is common.

The ecological consequences of this wholesale pollution of watersheds extend far beyond farm states. In 1972, scientists identified the Gulf of Mexico hypoxia—a so-called dead zone of algae-choked water that failed to support aquatic life, attributed to runoff from the Mississippi River. By 1997, the EPA established a task force to coordinate a response among state, tribal, and federal entities. Initially, eight states came to the table, but one was most responsible for the dead zone: Iowa. Even though the state has just 4.5 percent of the land area in the greater Mississippi watershed, it contributes about 30 percent of the nitrogen to the Gulf of Mexico. In 2015, the task force set a goal to reduce the Gulf hypoxia to about 2,000 square miles by 2035. Over the past five years, it has averaged close to triple that size. Last summer, it grew to around 6,334 square miles, larger than the state of Connecticut.

SETH WATKINS'S farmhouse sits on a steep hill, surrounded by slanted knolls and wooded gullies. We took shelter from the heat in the air-conditioned cab of his pickup, rumbling along dirt roads to the various plots his family has maintained or acquired since his great-grandfather settled here in 1848.

Watkins first started thinking about the health effects of poor water quality in the early 2000s, when both of his children were born with rare, nonheritable birth defects. After his second child went into surgery as a newborn, a nurse said to him, "We see you farm for a living. Where does your family get their water?"

The question rattled Watkins and eventually set him on a mission to understand how humans are affected by the pesticides, fertilizer, and manure that wind up in drinking water across farming regions. He researched the quality of his own water, which came from a nearby municipal treatment plant, and learned that it contained high levels of nitrates and coliform bacteria. "I'll probably never know for sure if farm chemicals caused my children's birth defects," Watkins said in a recent TED Talk. "But I can't prove they didn't." To avoid further contamination, he installed a reverse-osmosis filter in his kitchen. Then he overhauled his farm with new attention to protecting water.

Watkins raises cattle and grows oats, barley, and other crops in the Southern Iowa Drift Plain, a sloping, highly erodible region. He builds fences to keep livestock away from areas near water, plants trees in the creek beds to mimic the forested bottomlands of precolonial times, and sets his row crops back from delicate riparian areas.

Watkins parked his truck on a farm road near a small hill. To the right was land he managed. The plot was bursting with vegetation, buffered with hay on the water-adjacent edge and carefully contoured to stall erosion; on the left was his neighbor's plot. A gully had formed at its border, and the bare soil looked scarred and dusty. Some of the adjustments Watkins has made are technically required for farmers to receive crop insurance, but oversight is nonexistent. As we drove on, Watkins pointed to violation after violation. With nearly 25 percent of farmer income coming directly from the US Department of Agriculture, Watkins sees no excuse for not practicing sensible land stewardship. "What gives me the right to receive these [public] funds to farm, and we have zero regulation?" Watkins asked. "We are a totally unregulated industry."

David Cwiertny is the director of the University of Iowa's Center for Health Effects of Environmental Contamination. He said that Iowa is an epicenter of environmental contamination like no other state in the country, with water being the primary conduit. "Our environmental exposures are pretty darn complex because of the chemical intensity of how we produce animals and crops," he told me when I contacted him after my visit with Watkins. He researches the impacts of "heavily used but understudied chemicals," and while he is concerned about the estimated one-third of Iowans whose drinking water contains elevated levels of nitrate, he's more worried about the vast quantity of chemicals whose effects we have barely begun to understand. Every year, weed killers are applied to 85 percent of Iowa's 22 million acres of cropland. In addition, the majority of corn seeds on the market are now coated with insect or fungus repellents, which makes the diffusion of toxic chemicals into groundwater ever more pervasive.

The United States has one of the most lax regulatory regimes for agricultural chemicals in the world. European companies such as Bayer and Syngenta export compounds that are banned in the EU and sell them to America's farmers. In a typical year, fertilizer and crop-chemical sales in Iowa exceed $3 billion.

When it comes to agrichemicals, Cwiertny said that we have "a lot more questions than answers," adding that the science is well behind on documenting their effects. "We're polluting, and then we're not even asking the question of what the risks are, because we aren't collecting the data."

Cwiertny is also pursuing research on the potential effects of growth hormones, fertility-synchronization drugs, and antibiotics that are used heavily in the livestock industry. As an example, he pointed to a 2018 warning posted by the FDA about agricultural worker exposure to Altrenogest, a drug used in the hog industry to keep pigs breeding in sync. Men and women who were exposed to the drug, even just on a barn surface, not only experienced rashes, fever, vomiting, and other symptoms but also suffered reproductive problems like missed and abnormal menstruation and loss of libido.

Drugs like these are lightly regulated by the FDA for worker safety, but Cwiertny argues that it's also important to study people's low-level exposure to these chemicals through groundwater. "There's preliminary data out there that suggests we need to be getting our head around these issues and figure out what the risks are to Iowans, and we just aren't doing it."

Watkins pulled his truck over, and we walked across a sandbank to the edge of the West Nodaway River. It's one of the most polluted waterways in the state, but you would never know just by looking at it. As we watched its gentle currents ripple by, we talked about how southern Iowa, with its hilly vistas, wooded riverbeds, and terraced meadows, deviates sharply from the flat Field of Dreams stereotype. "It can be breathtakingly beautiful," Watkins mused. "It's actually a pretty neat area to live. But you're going to want clean water. You're going to want things you enjoy."

MY RESEARCH INTO Iowa's water issues inevitably led me to Chris Jones, a University of Iowa scientist at the Iowa Institute of Hydraulic Research who writes a widely read blog on the topic. In short, to-the-point posts with headlines like "Don't P Down My Leg and Tell Me It's Raining" (the P is a pun for phosphorus) and "Cry Me a Raccoon River," Jones expounds on why Iowa's water is bad and why, in his view, it's not getting better. He has also coauthored numerous opinion pieces in state newspapers, and in October 2021 launched a podcast with Cwiertny and University of Iowa professor Silvia Secchi. Through his role with the institute, he has access to the most comprehensive water data in the state, and he's worked for the Iowa Soybean Association as well as Des Moines Water Works.

Jones directs his harshest words at the agriculture establishment: "When will farmers and the industry in general ever take responsibility for the negative consequences that happen beyond the field?" he asked in one blog post. But he's critical of politicians, too, and even environmentalists, whom he thinks have "no cohesive message." The public's unwillingness to demand accountability enables all of it to continue—as he titled one essay, "Everyone's Responsible So No One's Responsible."

Jones gets the most responses when he calls for the regulation of Iowa's farmers. "We need to have the courage to tell farmers, 'You shouldn't do that,'" he told me when I met with him last summer via Zoom. In contrast to Jones's sometimes impassioned writing, I found him to be patient and plainspoken. Our conversation left me with the distinct impression that his indignation has metastasized gradually, over a long career examining solvable problems that, despite mounting human and environmental consequences, continue to get worse.

"Truth be told, I'm probably an average scientist at best," Jones wrote in another post. "But I'm not going to let that stop me from saying this: The ongoing pollution of Iowa's water is a moral wrong, and it's unjust."

Practically every Iowan has a personal connection to agriculture, and the industry holds an iron grip on the state's politicians. Powerful interest groups—primarily the Iowa Farm Bureau, which spends up to $350 million lobbying state and federal legislatures every year—perpetuate the narrative that the state's economy depends on the well-being of farmers and that any form of regulation constitutes an attack on agriculture itself.

The irony is that better stewardship of water can actually be profitable for farmers. Factoring in savings on equipment, labor, and other inputs, 10 to 15 percent of most Corn Belt plots are more economical to leave alone than plant. Those acres also tend to be the most environmentally sensitive, so growers can often pick up a subsidy for not farming them. This leads some critics to conclude that lobby groups oppose regulation so vehemently not because it would hurt farmers but because it would cut into the bottom line of the businesses that fund the lobbying—specifically the seed and chemical companies and the livestock industries, whose business models depend on wanton manure spreading.

The agriculture establishment doesn't deny that nutrient pollution is a problem. Its response to criticism has been to champion voluntary measures. Case in point: In 2008, the EPA mandated that states come up with a plan to do their part to shrink the Gulf of Mexico's dead zone. With heavy input from the agricultural lobby, Iowa produced such a document in 2013. Commonly referred to as the Nutrient Reduction Strategy, or NRS, it set the goal of reducing nitrogen and phosphorus pollution by 45 percent, though no timeline was specified. The major caveat of the NRS—and one of the highest priorities of the farm lobby—was that all of its provisions were voluntary.

Neil Hamilton, an emeritus professor at Drake University Law School and a former director of the university's Agricultural Law Center, sees that approach as a nonstarter. "The idea that we're going to somehow achieve clean water . . . on an entirely voluntary system—that's just magical thinking," he told me over Zoom. "There's no good reason to think that it could happen."

On its website, the Iowa Farm Bureau touts encouraging statistics to show that a voluntary approach is working: Between 2017 and 2019, cover crops increased by 36 percent. Since 2013, 400,000 acres of wetlands have been restored, and farmers have reduced tillage on millions of acres. So far, though, these efforts have only reduced nitrogen runoff by 1.6 percent. Furthermore, during this same period of "progress," enough land was converted from pasture and hay to cornfields that it increased the amount of nitrogen runoff overall.

Simply put, not only has the NRS failed to improve water quality, but it hasn't even stopped the state from backsliding, despite about $500 million in state funding for projects every year. When the Iowa Environmental Council projected how long it would take to accomplish the stated goals of the NRS, it found that the state was operating on "geologic timescales."

There is one voluntary practice that could make a meaningful difference in the effort to repair Iowa's water quality. It involves planting an area of vegetation known as a saturated buffer between fields and waterways. A water control box is installed with pipes to channel water draining from the field to vegetation that absorbs excess nitrogen. Once installed for a maximum cost of $5,000, the saturated buffer can last for 50 years.

Last summer, a coalition of state, county, federal, and private entities in Polk County streamlined the funding and design process and installed 41 buffers (the state had installed only 150 in the previous decade). The project is being hailed as a model for how water-quality initiatives can circumvent cultural and political roadblocks.

It's hard to imagine farmers and landowners refusing a project like this. Taxpayers foot the bill, government employees and contractors do all the work, and once the buffers are in place, farmers can forget about them. But farmers still hesitate to try them, especially when the first point of contact is the government. "You're never gonna sell a [buffer] to a farmer on 'this will improve your farm,'" because they're not going to see a direct benefit, said Tony Lem, a farmer in Polk County who installed buffers on his fields "to do the right thing."

If enough buffers were strategically placed in every county, they could add up to real change. This has yet to happen at scale in even one of Iowa's 99 counties. Jones and other critics have compared the buffers to Band-Aids, but others argue that with no comprehensive strategy on the horizon, they are better than nothing.

Jones is quick to point out that effective regulation wouldn't have to entail a total overhaul of the system. He suggests, among other changes, measures like banning row-crop farming in the two-year floodplain (just 400,000 of Iowa's over 33 million farm acres) and prohibiting the spreading of manure on snow and frozen ground. He'd also like to see rules that prohibit tilling in the fall and limit the quantity of fertilizer used by farmers to that advised by Iowa State researchers. And he advocates for stricter permitting criteria for confinement animal barns.

But he's not expecting such policies to materialize anytime soon. That would take "courage from the highest levels," he wrote in one blog post. "And we just don't have that kind of courage right now in Iowa, or nationally for that matter. It's so painfully obvious."

This article appeared in the Spring quarterly edition with the headline "The Trickle-Down Effect."