First-ever ban on watering lawns in central Iowa due to nitrate levels in rivers

A ban on watering lawns has been issued in the Des Moines metro area for the first time to avoid a potential water crisis due to high concentrations of nitrates in local rivers.

Last week, the Central Iowa Water Works banned about 600,000 commercial and residential customers from watering lawns as near-record levels of nitrates in the Des Moines and Raccoon rivers threaten to overwhelm the water utility company's capabilities to treat the water.

There is an "imminent risk" of violating nitrates standards set by the U.S. Environmental Protection Agency, according to a press release by the Central Iowa Water Works.

The treatment plant has been using the nitrate removal facility for more than two months, and nitrate removal processes are operating at full capacity, the utility company said.

"Our plants have been having a difficult time treating the high nitrate concentrations in the river, which means that our plants are unable to produce enough water to keep up with the amount of water that's being requested by the public," Tami Madsen, executive director of Central Iowa Water Works, said during a news conference on Thursday.

Nitrates are chemical compounds found naturally in the environment that can also be produced in various industrial and agricultural applications. High nitrate levels in the water supply can have adverse health impacts on humans.

The water ban was issued with the intent of producing enough water for "lifeline essentials" as the nitrate contamination causes water supply challenges in raw water sources. Lawn irrigation is "by far" the largest source of increased water demand in the summer, the city of Waukee said in an emergency alert issued last week.

"We are pulling all levers at our treatment facilities and nitrate removal processes to prevent a violation," Madsen said in a statement.

The water utility company is bringing water from the Des Moines and Raccoon rivers and treating a portion of that water by running it through a reverse osmosis system, which will remove nitrate levels, Larry Weber, director of the University of Iowa's IIHR—Hydroscience & Engineering, told ABC News.

There is a certain volume restriction on how much water can run through the nitrate removal system, Weber said. If residents were to keep using water for "unnecessary" means, the water utility company wouldn't be able to treat enough of it to blend back with the untreated water and still meet the EPA standard, Weber said.

The EPA sets a maximum containment level of 10 milligrams per liter -- equivalent to 10 parts per million. The standard is to protect infants under 6 months, who can become seriously ill and die if untreated, if exposed to high levels of nitrate, according to the EPA. Effects include risk of methemoglobinemia -- also known as blue-baby syndrome -- and shortness of breath, according to the EPA.

Fertilizer and manure runoff across agricultural fields are often the culprit for the presence of nitrate in rivers, according to the EPA. Spring rains, especially when following drought conditions, can increase nitrate levels in rivers, research shows.

The rain that the region has experienced so far this year follows multiple years of dry patterns, Weber said.

During the dry years, nitrates from commercial fertilizer application and livestock manure application to the land can accumulate in the soil. Then, once moisture comes, the drainage system of the landscape pulls those chemicals into the waterways, Weber said.

"It's pulling water through the soil column and discharging it back to our streams with very high nitrate concentrations," Weber said.

The restriction on watering lawns is no longer voluntary, as requests in recent weeks to bring down water usage has not resulted in any noticeable reductions, said Madsen, the head of the water utility. She said the water utility now needs "full cooperation" from the public.

"Whatever you can do, from the standpoint of citizen, to help cut back on your water use, please do it right now," said Des Moines Mayor Connie Boesen during the news conference.

Any residential or commercial customer observed by the water utility watering their lawn will be notified of the violation via a tag left on the property, the water utility company said. If the watering does not cease within 48 hours, water service could be cut off, the City of Des Moines warned.

All watering of gardens should take place with a handheld container, and not using a sprinkler or hose, officials said. The city of Waukee even encouraged residents to utilize leftover water from half-full drinking glasses or from rinsing produce to water potted plants.

Sod installed in 2025 can be watered with the "least amount of water necessary for plant health," and no new sod should be laid until the crisis is over, the city of Johnston said in a statement.

Water authorities also asked customers to avoid washing cars and filling pools. Some cities shut off public pools, splash pads and golf courses.

In the event that conditions worsen, the next step would be to ration water.

"But that's not even on the radar," Madsen said during a news conference on Monday. "If we all work together, and get through the next few weeks, we won't even have to have that discussion."

The lawn-watering ban is expected to last until further notice, the water utility company said.

Treated drinking water continues to meet all state and federal regulations for drinking and household uses, the water utility company said. Des Moines has a single municipal drinking water distribution system, which treats water for human consumption as well as for other needs, such as washing cars, sewage and lawn care, Weber said.

"We are meeting the safe drinking water standards. Your water is safe to drink," Madsen said. "But without your help, we are not going to be able to continue to produce water that meets the EPA for nitrate."