A Wisconsin city spends $200,000 a year to keep farm nitrates out of its tap water

Chippewa Falls, Wis., has long been a place where clean water was part of the identity. The city’s municipal supply helped sustain a brewing tradition, and for many residents the tap was never a source of worry. These days, keeping it that way costs about $200,000 a year.

The city’s water is piped to roughly 16,000 customers and stays under the federal nitrate limit of 10 parts per million. That wasn’t inevitable. In 1997, utility managers found troubling nitrate levels in a city well. Chippewa Falls responded by adding treatment and pulling from deeper, cleaner aquifers, according to Circle of Blue.

The work has kept municipal water safe, but the protection stops at the city line. Chippewa County has about 67,000 people on private wells, and many are drawing water tainted by nitrates from fertilizers and manure. The city can treat its way past the problem. Rural households often cannot.

The contrast shows up in the daily life of Matthew Boos, supervisor of the city’s water treatment plant. He lives outside the city and relies on a private well. When he moved in, the water tested at 10 parts per million — right at the federal cap. “It was 10 when I got there,” he told Circle of Blue. “Now it’s 20.”

Nitrates form when nitrogen from fertilizer or manure combines with oxygen and slips into the groundwater. Research has linked them to cancers of the blood, brain, breast, bladder and ovaries. Circle of Blue cited studies showing higher risks of colorectal cancer, thyroid disease and birth defects at nitrate levels around five parts per million — half the federal cutoff.

The federal cap is not a modern safety threshold. It was set in 1962 to prevent blue baby syndrome in infants, treated as a temporary standard in 1975, and formally adopted as a standard in 1992. It has never been revised, even as the science around nitrate health risks has grown.

That leaves millions of people exposed to water that may not meet current scientific understanding. An Environmental Working Group analysis cited by Circle of Blue found nitrate levels of 3 parts per million or greater in drinking water serving more than 62.1 million Americans across 6,114 community systems. In a separate study, 85% of more than 50,000 U.S. water utilities had no nitrate treatment capacity.

Wisconsin is not immune. State data show nearly one in ten private wells tested in Wisconsin exceeded the nitrate health standard. Wisconsin farmers also used about five times as much nitrogen fertilizer in 2019 as they did in 1960.

Chippewa Falls is uncommon because it decided to spend. Boos said the city treats about 4 million gallons of drinking water each day. For municipal customers, that means a layer of protection many rural households still lack.

For people outside the public system, the choices are expensive. They can install reverse-osmosis filters, test wells regularly, or pay to drill deeper wells into less contaminated aquifers. Boos installed a reverse-osmosis system at his home. His parents received a state grant to drill a new, deeper well.

The county has also set up four water refill stations where residents can bring bottles and larger containers. That helps in the short term, but officials and advocates say it is not a lasting answer.

Tyler Lobdell, a staff attorney with Food & Water Watch, said voluntary runoff programs won’t be enough. The core problem, he argues, is broad agricultural pollution generated with limited oversight.

“We treat 4 million gallons a day,” Boos said. “It’s safe to drink. I tell people I would take city water, municipal water, over well water here any day, especially in this region.”

Chippewa Falls is not alone in facing these choices. Across the country, communities are wrestling with water supply and pollution issues that strain budgets and reshape everyday life.

• In Cochise County, Ariz., local residents are trying to stop rural groundwater from being drained to support farms and development.
• In Cave Creek, Ariz., the shrinking Colorado River has pushed the town to reactivate unused wells, slow growth and enter new water agreements — steps drought-hit communities once hoped to avoid.
• In Pennsylvania, a retiree lost household water after nearby data centers overwhelmed the local system.

These kinds of conflicts rarely stay within one property line. Cleanup costs, damaged supply and weak oversight can affect daily life for years. Chippewa Falls chose to pay for treatment and share the cost across its municipal customers. For much of the region, the question remains open — and the tab keeps growing.