Warming Winters Intensify Nitrate Pollution in Iowa's Drinking Water

Wed Apr 01 2026 16:49:22 GMT+0000 (Coordinated Universal Time)

The ongoing issue of nitrate pollution in Des Moines has been exacerbated by warmer winters, leading to increased costs for water treatment. Experts are concerned about the long-term implications for public health as climate change impacts water quality.

Des Moines, Iowa is facing rising costs and health risks from increasing nitrate pollution in its drinking water. A special filtration system is frequently required, which experts attribute to warmer winters linked to climate change. This trend suggests a growing public health concern as more agricultural runoff enters waterways.

When pollution gets bad enough in the rivers supplying Iowa’s largest city with drinking water, it costs Des Moines around $16,000 a day to run a special system to filter out dangerous nitrates. It’s a fact of life in the agriculture-dependent state — and climate change is worsening water quality.

Nitrates from fertilizers and pesticides have historically seeped into soils and waterways like the Raccoon and Des Moines rivers, but this year unusual winter conditions forced additional filtration efforts in January and February, marking just the second time in over three decades that such measures were needed in the winter. Residents may face higher water bills as the state’s water sources remain vulnerable.

Experts attribute these problems to warming winters, noting, “We are more apt to see these in the future,” according to Justin Glisan, Iowa’s state climatologist. The warming climate is creating conditions where melting snow or rain can carry more nitrates into the waterways, posing long-term threats to public health.

Why warmer winters lead to more water pollution

Pesticides and fertilizers used in farming contribute nitrogen and phosphorus, which is washed into drinking water during rains or snow melts. The health risks associated with high nitrate levels include serious conditions like blue baby syndrome, posing dangers particularly for infants. Areas with less plant life in winter can result in higher nitrogen flow downstream, aggravating the nutrient pollution problem.

Nitrate pollution is not just a problem for big cities; low-income and rural communities often lack the infrastructure to address water quality issues effectively. Communities heavily reliant on well water, which can be contaminated with nitrates, face higher costs for testing and filtration while smaller municipalities may struggle with an inability to filter nitrate levels.

Regulating nutrient pollution has proven difficult

The challenges are compounded by a strong agricultural lobby that resists mandatory regulations. Politically, states have delayed significant action to mitigate nitrate runoff, even as pollution levels rise. Some advocacy groups are pushing for more accountability from polluters, emphasizing the need for both conservation efforts and systemic changes in agricultural practices to protect water quality.

As Iowa prepares for future winters with more nutrient pollution, proactive measures and responsible watershed management are seen as crucial to combating these growing health concerns.