Nitrate and E.coli levels have been detected in Iowa’s rivers and lakes, forcing cities to temporarily stop drawing from contaminated sources, but Ames water remains safe.

“We’ve really had no changes in overall water quality from our wells,” John Dunn, director of water and pollution control for the city of Ames, said. “We are monitoring those wells routinely for multiple parameters, including nitrate and E.coli, and we’ve not detected the presence of either of those contaminants this summer.” 

The Des Moines Water Works recently faced a water shortage after elevated nitrate and bacterial levels made the Raccoon River unusable for treatment. 

While Ames is geographically close, its water system relies on a different kind of source, which is the Ames aquifer, a high-quality groundwater formation. 

“Our aquifer formation is highly reduced,” Dunn said. “That means any nitrate that enters the aquifer from surface water gets converted to ammonia. So when it comes out of the wells, there’s no nitrates left.” 

Dunn noted that the ammonia is actually reused in Ames’ disinfection process, allowing the city to form stable chloramines. This contributes to the city’s reputation for clean water. 

“Ames was named best tasting water in Iowa for the fourth time in eight years, and recently earned third place in a North American taste competition held in Denver,” Dunn said. 

While drinking water within Ames is in good shape, recreational waters across Story County have faced challenges this summer, according to Sara Carmicheal, watershed coordinator for Story County Conservation. 

“We have had high levels of both contaminants of nitrate and E.coli this summer,”  Carmicheal said. 

Carmichael also noted that spikes of these complaints are often tied to rainfall and runoff. 

“It’s hard to give a specific answer. Water quality should be looked at throughout the years, not just on a snapshot in time,” Carmicheal said. 

Carmeicheal noted that the Story County Conservation is often watching different public locations for contaminants. 

Sites like Peterson Park and Hickory Grove Lake are monitored weekly from Memorial Day to Labor Day, with McFarland Lake recently added to the list following a restoration project. 

“Peterson Park has not had any elevated E.coli levels this year or in the past, because that area is fed by an underground aquifer,” Carmichael said. 

However, Carmichael still urges caution to the public. 

“Avoid swimming after a heavy rainfall. That is when bacteria and other constraints can be higher,” Carmicheal said. 

The challenges extend beyond individual communities, reflecting a border issue across the state.

“The most pressing challenges in these watersheds are the elevated levels of nitrate and phosphorus. These nutrients can contribute to algal blooms, degraded drinking water sources, and downstream impacts such as the Gulf of Mexico hypoxic zone,” Adam Schniders, water quality resource coordinator for the Iowa Department of Natural Resources (DNR), said.  

Schneiders expressed that the DNR uses multiple tools to monitor Iowa’s water, including fixed sampling stations, fish and insect studies and biological health assessments. 

Despite the data, Schneiders expressed that there are success stories where cover crops, wetlands and buffer strips have helped reduce contamination. 

“Even when the right practices are in place, water quality improvements can take years, or even decades to materialize,” Schniders said. 

While Ames has not faced contamination like Des Moines, Dunn emphasized that Ames water pollution and control is still investing in upstream solutions. The city is currently building a $55 million upgrade to its wastewater treatment plant to reduce nitrogen discharge by two-thirds. 

“This investment alone will only reduce the total nitrogen load in the South Skunk River watershed by about 5%,” Dunn said. “That shows just how big of a watershed-scale problem this is.”

Dunn mentioned the need for partnerships to continue to make Ames’s water safe.

“We’re partnering with Story County Conservation, SWCD, and IDALS to install saturated buffers and tile bioreactors on farms north of Ames,” Dunn said. “By diverting tile drainage water through these systems, we can remove nitrates before they enter the Skunk River.”

Protecting source water, rather than relying solely on treatment, remains a key priority for communities across Iowa. 

“It’s far better to prevent contamination in the first place than to try and remove it from drinking water after the fact,” Dunn said.