EPA is forcing Minnesota to address farm pollution in drinking water. Is Iowa next?

This month, the U.S. Environmental Protection Agency directed Minnesota to take action against agricultural pollution tainting thousands of private wells in the southeastern portion of the state.

A Nov. 3 letter from the EPA to the Minnesota Pollution Control Agency and state departments of health and agriculture called attention to health risks from groundwater nitrate contamination for residents in eight counties in the state’s karst region.

Nitrate, a form of nitrogen, is a pollutant in waterways and groundwater that typically originates from agricultural runoff. It is linked to blue baby syndrome when its levels exceed 10 milligrams per liter in drinking water. Long-term exposure to lower nitrate levels, even for adults, could lead to cancer and other negative health impacts, some emerging research suggests.

The EPA is now requesting that Minnesota develop a plan for addressing this pollution, which primarily comes from agriculture, and identifying and notifying impacted residents. It recommended the state adopt more requirements for sources of nitrate pollution, including feedlots and fertilizer application.

Iowa shares a border with Minnesota, as well as the karst geography that makes groundwater especially vulnerable to agricultural contamination. With similar nitrate pollution levels in its private wells, could Iowa be subject to similar EPA scrutiny?

What happened in Minnesota?

The Minnesota Well Owners Organization, a nonprofit focused on safe drinking water for private well owners, approached fellow nonprofit Minnesota Center for Environmental Advocacy in fall 2022 about groundwater contamination in southeast Minnesota.

Last April, they banded together with other organizations, like the Environmental Working Group, to file a petition with the EPA for emergency action under the federal Safe Drinking Water Act to address contamination in the area.

More than 380,000 residents populate southeastern Minnesota, and about 80,000 of them rely on private wells for drinking water. Decades of well sampling in the area have consistently uncovered nitrate levels that exceed the safe drinking water standard.

Across its various governing bodies, Minnesota has not done enough to address the contamination, the groups said in the petition. They said most nitrate contamination in the region is caused by “harmful agricultural practices on groundwater recharge areas that are not sufficiently addressed by Minnesota regulators” and called on the EPA for federal action.

“State and local officials have failed to do what is needed to correct the pervasive threat to human health,” the April petition read. “EPA is fully empowered under the (Safe Drinking Water Act) to take emergency action to protect human health in the karst region of Minnesota given present circumstances.”

On Nov. 3, the EPA published its response to the petition, ordering Minnesota state agencies to band together to remedy the situation.

About 9,200 residents in southeast Minnesota are at risk of consuming elevated nitrate levels in their drinking water, the agency said. The Minnesota Department of Agriculture reported that 12.1 percent of the tested private wells there exceeded the federal standard of 10 milligrams per liter for nitrate. Several public water systems in the area have had to drill deeper wells or implement additional treatments to avoid elevated nitrate levels.

The agency outlined immediate steps Minnesota needed to take to address the health risks, including identifying and notifying residents with contaminated private wells, providing them with alternate water sources and giving quarterly progress reports to the EPA. It also made recommendations for longer-term solutions for nutrient pollution in the state, like adopting more monitoring requirements for animal feeding operations and modifying state standards for manure and fertilizer application.

The EPA said it expects Minnesota to “hold sources of nitrate accountable” for reducing their pollution using all available tools. It also warned that it would “closely monitor this situation and consider exercising our independent emergency and enforcement authorities.” Minnesota has 30 days to respond with a plan of action.

The petitioning organizations were pleased with the EPA’s response, said Leigh Currie, the Minnesota Center for Environmental Advocacy’s director of strategic litigation who authored the petition.

“It’s an issue that's getting some more attention finally, and EPA is paying more attention to it,” she said. “I'm hoping that their response in Minnesota means that they're going to start to taking a hard look at what's happening in other places as well.”

How does it relate to Iowa?

Minnesota’s karst region hugs the state’s southeast corner. Karst landscapes are made up of limestone and other rocks that dissolve in water over time, causing caves and sinkholes.

Water typically runs off landscapes into waterways or percolates through soil to get to groundwater. But karst regions can feature a maze of underground drainage systems that intertwine unfiltered surface water — and any contaminants it may hold — with groundwater that some wells dip into.

In southeast Minnesota, where there’s industrial row-crop agriculture and large-scale animal agriculture facilities atop karst, the groundwater is more susceptible to nutrient contamination. That karst landscape — and its vulnerabilities — stretches into Northeast and East Central Iowa, said Keith Schilling, the state geologist of Iowa.

“It's extremely vulnerable,” Schilling said about groundwater in Northeast Iowa. “Despite all the best management practices you could install, agriculture is a leaky system. You're going to lose nutrients — nitrate, in particular — to groundwater. … If we continue to farm in these vulnerable areas, there's only so much you can do to reduce that loss.”

About 1 in every 10 Iowa residents depends on a private well for drinking water. Private wells are not regulated under the Safe Drinking Water Act, so owners are responsible for their upkeep and monitoring. Yet less than 10 percent of the state’s nearly 100,000 active private wells had any water test sample collected in 2020, making statewide well testing data incomplete.

The percentage of Iowa private wells with elevated nitrate levels has varied in the past two decades, as has the number of wells tested, according to state data. Statewide rates of elevated nitrate levels peaked in 2014, when 29 percent of all tests contained nitrate levels that exceeded the federal standard of 10 milligrams per liter. In 2020, almost 10 percent of the tested private wells had elevated nitrate levels.

Several counties in Eastern Iowa, particularly in Northeast Iowa, have consistently seen higher percentages of elevated nitrate levels compared with the state average.

Delaware County consistently sees high nitrate levels in between 18 and 30 percent of its tested wells. More than two-thirds of Clayton County’s 169 private wells tested for nitrate contained elevated levels in 2016. The amount of nitrate-tainted wells in Jackson and Clinton counties regularly surpasses the state average.

“EPA weighing in on a nonpoint source issue is kind of a surprise,” Schilling said. Nonpoint sources include fertilizers, herbicides, sediment, bacteria and nutrients that pollute waterways through runoff and similar avenues. “But the data that everybody's looking at is not a surprise.”

Is Iowa next?

Despite the parallels, it’s unclear if the EPA’s actions in Minnesota would directly impact Iowa, its private wells and any of its regulations. For one, Minnesota falls within EPA Region 5; Iowa lies in EPA Region 7.

“Even though we share so many similarities between Northeast Iowa and Southeast Minnesota, we're in very different EPA regions under different EPA management philosophies,” Schilling said. “As much as you think there'll be a uniform response, I don't know if you could expect that.”

EPA Region 7 does not currently have plans to submit a similar request to Iowa, lead press officer Shannan Beisser said in an email. The agency has not received any petitions or complaints concerning nutrient contamination from Iowa’s private wells.

“However, we work in partnership with the Iowa Department of Natural Resources to address nutrient pollution issues affecting water quality within the state under our legal authorities,” she added.

In response to an interview request from The Gazette, the Iowa DNR pointed to resources for private well owners that it supports in conjunction with the Iowa Department of Health and Human Services.

“We encourage anyone who has concerns about their wells to take advantage of the statewide grant program, Grants to Counties Water Well Program, that can provide you with basic water testing for free,” said Iowa DNR spokesperson Tammie Krausman. “For more information, please contact your local county environmental health (officials).”

The Iowa Chapter of the Sierra Club may consider taking similar actions to address nutrient pollution in private wells in Iowa as the Minnesota Center for Environmental Advocacy did, said legal chair Wally Taylor.

The organization had filed a petition to the EPA in 2007 to investigate the Iowa DNR’s oversight of concentrated animal feeding operations, or CAFOs, that discharge into waterways. In 2021, the Sierra Club also successfully sued Supreme Beef — an 11,600-head cattle feedlot near Monona in Northeast Iowa — and the Iowa DNR to reverse the approval of the feedlot’s nutrient management plan. Supreme Beef applied again in October.

“The Sierra Club has been fighting CAFOs for years. And, frankly, we've been focusing on the surface runoff into the streams and haven't paid that much attention to the wells,” Taylor said. “I think we're going to have to take a closer look at that.”

The Iowa Environmental Council has been following the Minnesota nonprofits’ petition since it was filed, said the council’s staff attorney and interim executive director Michael Schmidt. He said while the council was glad to see the EPA take drinking water hazards seriously, it may not set a precedent that Iowa could be subject to.

“It's based on the facts that were in the petition that the Minnesota groups filed, and the facts will be different in other places. They may be similar but not identical,” he said. “In a different state with a different regional administrator and different facts, that might lead to a different conclusion.” He added the council is looking into similar actions as the Minnesota groups but couldn’t share more details.

For Minnesota, the EPA letter was a good first step in mitigating nitrate contamination in the area, Schilling said. But it marks just the start of remedying years of nutrient pollution.

“This has been a problem decades in the making, and it is going to take at minimum decades for the solution,” he said. “That nitrate is here to stay for quite some time.”

Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; brittney.miller@thegazette.com