What to know about Iowa's water systems and EPA standards

In 2025, 97.4 percent of Iowa’s public water systems complied with EPA standards, according to a report from the state natural resources department.

There are 1,815 public water systems in the state that have to meet the federal Safe Drinking Water Act.

The annual report tallies any health or reporting violations of the act.

“This is basically a large-scale snapshot of all of our drinking water monitoring in the state,” says David Cwiertny, a professor and researcher at the University of Iowa. He’s the director of the Center for Health Effects of Environmental Contamination. “The DNR will always point out how the overwhelming majority of our community water systems are fully compliant. … That is not something we should not be taking for granted, as it gets harder and harder for many of them to manage source waters that are becoming more impaired through runoff or less reliable through climate change.”

The 2025 report covers the state’s public water systems of all sizes, from a convenience store to a larger municipal water utility.

In 2025, the number of nitrate health violations was 36, up from 14 in 2024.

Of the 13 systems that had those violations in 2025, eight were smaller systems that don’t serve permanent residents.

“I think that’s important context because we know those smaller systems that are things like truck stops and campgrounds are ones that tend to be more challenging to maintain quality,” Cwiertny says. “Nitrate is one of these tricky things.”

Nitrate is monitored as an immediate health threat because of the risk it poses to infants. The EPA set a standard for the pollutant based on “blue baby syndrome.”

Heidi Cline works for the DNR. She helps put the report together.

She wants Iowans to know that they can find the current compliance report and past ones online.

“I want them to be able to trust their drinking water. I drink my tap water at home,” she says.

Cline says the DNR works with any system with a violation. In fact, some tallied in the 2025 report have been addressed.

“Some of these issues are already fixed,” Cline says. “We don’t allow long chronic violation of the nitrate maximum contaminant level to happen. You have to do something if you have an issue.”

The maximum contaminant level for nitrate is 10 milligrams per liter in treated drinking water.

The report covers more than nitrate.

“It’ll look at everything that’s regulated radium, lead and copper under the lead and copper rule,” says Cwiertny. ” Other things we struggle with would can be things like arsenic, different types of bacteria, disinfection byproducts.”

There are two main types of violations in the report: those related to public health issues and then reporting violations. That could include not filing a document correctly.