Ag fertilizer runoff likely will force more drinking water restrictions

[douglas9]

Iowa lawn, pool bans underscore growing risks of nitrate pollution.

For nearly a month, hundreds of thousands of Iowans have not been allowed to water their lawns — even though there’s no drought.

Local authorities previously asked the public to refrain from washing cars and filling pools. And some cities turned off splash pads in the height of summer heat.

While such measures are common during dry periods, there’s no shortage of water: Rather, the water in and around Des Moines contains too much nitrate, a natural component of soil and a byproduct of commercial fertilizer and livestock manure. Persistent rainfall has flushed nutrients out of fertilized fields into streams and rivers.

While the water bans are temporary, they’re the starkest sign yet of the state’s long-brewing struggle with high nitrate levels in streams and rivers that supply drinking water.

“It’s a big deal: the first time ever that lawn watering has been banned,” said Tami Madsen, executive director of Central Iowa Water Works, a regional water authority serving 600,000 people.

Federal law limits nitrate levels in drinking water because of its association with infant asphyxia, also known as blue baby syndrome. And a growing body of research has found links between nitrate consumption and cancer.

While Iowa’s problems are uniquely severe, nitrate levels are a rising concern in other regions, from California to the Chesapeake Bay. And climate change is expected to worsen the problem as more intense cycles of drought and severe storms increase farm runoff.

https://stateline.org/2025/07/10/ag-fertilizer-runoff-likely-will-force-more-drinking-water-restrictions/