Manure piling up

Study: State produces 108M tons, or 33 tons per Iowan

FERN ALLING

The Gazette

It’s unsurprising that Iowa has a large number of animal feeding operations — as the nation’s No. 1 pork producer, all of those hogs have to come from somewhere. But the Iowa Department of Natural Resources might not be tracking them all, according to a new analysis by advocacy nonprofit the Environmental Working Group.

The report claims to have identified 15,309 animal feeding operations in the state in contrast to the less than 11,000 operations represented in the most recent DNR data.

Together, those facilities produced an estimated 107.6 million tons of manure in the last year, or 33 tons of waste for each person in the state.

The amount of waste Iowa’s concentrated livestock operations produce contribute to water quality problems in the state, said Anne Schechinger, senior director of agriculture and climate research at the Environmental Working Group and a co-author of the report.

“There’s a really big public health implication for these facilities,” Schechinger said. “We know there’s nitrogen in manure that turns into nitrate in drinking water, which leads to increased risk of cancer.”

Tracking the animal feeding operations in the state is crucial for understanding how manure is disposed of and how it may be affecting water quality in turn. The report’s co-authors and a representative from the Iowa Environmental Council say its findings point to a need for greater regulatory oversight from the DNR.

METHODOLOGY AND FINDINGS

Generally speaking, animal feeding operations raise livestock by keeping them in confinement — usually a building, or tightly packed

Hogs feed in a pen in a concentrated animal feeding operation in Lawler, Iowa, in October 2018.

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in a feedlot without room to graze — and fed consistently until they can be sold. Since animals are sold by weight, said Michael Schmidt, general counsel with the nonprofit Iowa Environmental Council, this method gives farmers efficiency and consistency in what they’re selling.

Schechinger said the Environmental Working Group was interested in looking into animal feeding operations in the state after it completed a similar analysis in 2020 that looked at growth in large animal feeding operations. The previous analysis found those operations increased more than fivefold from 1990 to 2019, and the latest analysis showed a 13 percent increase between 2019 and 2025.

“It’s really a systemic issue,” Schechinger said. “Farmers have to have more animals to make money, and so that’s why economically you really see this increase in large facilities over time.”

To find where animal feeding facilities were in the state, Schechinger and senior GIS analyst Ethan Bahe started with the DNR’s publicly available feeding operations dataset and used aerial imagery from the U.S. Department of Agriculture to verify each entry was accurate.

Some of the addresses listed in the DNR database didn’t show as an animal feeding operation in the aerial imagery, Bahe said. Other listed facilities were clearly no longer in operation, as was the case with a facility missing its roof.

“DNR’s database is updated daily, but does not include all animal feeding operations in the state. The database does not include small confinements and open lots not subject to state or federal regulations,” TammieKrausman, communications director with the Iowa Department of Natural Resources said in a statement emailed to The Gazette.

After finding and verifying each animal feeding operation, the researchers estimated their size using U.S. Environmental Protection Agency classifications. Sizes are determined by the number of “animal units” an operation has, approximately 1,000 pounds of live weight. For example, one cow and about 56 turkeys would be one animal unit. Animal units provide a standard way of comparing animal feeding operations and the amount of manure each produces.

Under EPA definitions, small animal feeding operations involve less than 300 animal units, medium animal feeding operations hold between 300 and 999 animal units and large operations have 1,000 animal units or more.

The analysis found the amount of manure each facility produced was disproportionate to the number of facilities of each size in the state. While large animal feeding operations made up less than one-third of all animal feeding operations in the state, they accounted for nearly two-thirds of the 107 tons of manure produced.

The greater the size of an animal feeding operation, the more regulations, too. Operations with 500 or more animal units have to submit construction design plans to the DNR before building and send the agency a manure management plan annually. Facilities with 1,000 or more animal units require a construction permit from the DNR to be built, along with an annual nutrient management plan.

Bahe said the Environmental Working Group’s analysis showed there were 3,276 feedlots in the state that housed between 950 and 999 animal units, barely skirting the requirement for stricter regulations.

“You know that they’re doing that on purpose,” Bahe said. “That is a lot of facilities to be just below the threshold.”

In a statement sent to The Gazette, the DNR representative said the agency’s field offices completed roughly 750 inspections of facilities with manure management plans in 2025, around 50 of which were issued violations, including those related to manure application.

WATER QUALITY

All the manure animals produce has to go somewhere. Schmidt said it’s generally stored on site and later applied to fields or sold for others to use.

“Manure is a great fertilizer,” Schmidt said. “The issue in Iowa is the amount that gets produced in small areas.”

No confined facilities are allowed to put manure in the water, but there’s room for error in how manure is stored and used — the pits it’s kept in can leak into waterways, and improperly applied manure can drain into surface water after a rainstorm or into groundwater via tile drainage.

Manure contamination in the water supply increases the level of nitrates, which are linked to colorectal, ovarian, bladder and kidney cancer per a report from the Iowa Environmental Council. These risks could potentially still apply below the EPA limit of 10 milligrams per liter linked to blue baby syndrome.

“Rivers in Iowa, including the the Cedar River through Cedar Rapids, the Iowa River, the Des Moines River, the South Skunk River, all of which are used for drinking water have regularly been above 10 milligrams per liter,” Schmidt said. “Residents across the state are are affected by this.”

When reached for comment, a representative from the Iowa Pork Producers Association directed The Gazette to its website, which lists some of the following practices it says pig farmers in the state use to protect the environment:

■ No-till farming and cover crops to keep nutrients in the soil and out of water.

■ Precision application of manure as outlined in manure management plans with the DNR.

■ Re-purposing manure as a natural fertilizer.

REGULATIONS

Schechinger said turning regulation of animal feeding operations over to the counties they’re located in could be a potential solution, as it would give locals more control over what they will allow in their communities.

“From a political standpoint, it’s something that could have support from both parties because it’s the nature of giving more rights back to local communities,” Schechinger said. “It’s something that could actually work.”

But Schechinger and Schmidt both pointed out the need for more transparency and regulatory action by the DNR. Schechinger said the manure management plans the DNR requires for operations with more than 500 are not digitized for online use, and Schmidt said records of how the manure is actually applied are not publicly available.

Further, Schmidt said the agency receives $1.32 million annually for animal operation enforcement from the state legislature, an amount that hasn’t changed since 2014. Penalties for enforcement actions are capped at $10,000 per violation.

“We just need better oversight,” Schmidt said. “Penalties and DNR staffing are not adequate right now.”

Schechinger acknowledged that there may be flaws in the analysis and said the organization is willing to share their data with the DNR. Krausman said the agency reached out to the Environmental Working Group and has not yet received the full data set.

“We understand that there are limitations to our analysis, but we also know it shouldn’t be really our job to even be doing this,” Schechinger said. “There should be state bodies or federal bodies that are tracking every animal facility in the country, and we know there aren’t.”

Fern Alling is a general assignment reporter forThe Gazette.They can be reached at fern.alling@thegazette.com or (319) 398-8331.

Cattle graze Tuesday in a Benton County pasture.

MICHAEL BANIEWICZ/THE GAZETTE

Schmidt