Iowa's waterways face significant contamination from agricultural runoff, creating public health risks and limiting recreational opportunities across the state. More than half of monitored river, stream and lake sections in Iowa failed to meet state standards for swimming, drinking or aquatic life in 2024, according to state tracking data.

The pollution stems primarily from nitrates and phosphorus in fertilizer and manure that drain from Iowa's extensive corn, soybean and hog operations into the state's dense network of waterways. This agricultural runoff has made Iowa a leading contributor to the aquatic dead zone in the Gulf of Mexico. Last summer, Des Moines imposed water restrictions as officials struggled to remove harmful nitrates from tap water.

Bacteria contamination poses the most immediate threat to recreational water use, originating from livestock, wildlife and human sewage. Lake Darling, a 300-acre recreational lake in southeast Iowa, experienced the worst overall health of any state beach in recent years, with 10 weeks of E. coli advisories and six algal bloom warnings. The contamination has forced many residents to abandon traditional summer water activities.

Hannah Ray J Childs, a whitewater kayaker from Manchester, continues using the Maquoketa River despite getting sick from the water and now wears nose and ear plugs for protection. Mary Swander, a 75-year-old former state poet laureate, has stopped swimming after experiencing sticky water conditions and ranger warnings about water contact.

Iowa has invested nearly $100 million annually in addressing the problem, with Governor Kim Reynolds announcing an additional $320 million package for water infrastructure in May. The state relies on voluntary programs rather than mandates to reduce agricultural runoff, working with farmers on practices like cover crops and reduced tillage. Environmental groups recently sued the Trump administration over the reversal of Biden-era requirements for Iowa to address nitrate pollution in several rivers.

Farmers face economic pressures that complicate pollution reduction efforts. Supply and fertilizer costs have risen sharply, and return on investment for improved practices can take years to materialize. Demand for federal and state assistance to implement better practices exceeds available funding, according to agricultural educators.