Beach Advisories Hit an All-Time High: 2025 Monitoring Recapped

Since 2014, IEC has monitored and reported beach advisory statistics to promote public safety and awareness of harmful pollutants to Iowa’s recreational water bodies. This data comes from the Iowa Department of Natural Resources (DNR) AQuIA site, which serves as a public information portal to display the results of water monitoring conducted by DNR staff. DNR releases water safety reports weekly from Memorial Day to Labor Day. With last week’s advisories in the books, we reflect on another unprecedented year of Iowa beach advisories in our final summer edition of Weekly Water Watch newsletter. 

Regular precipitation in the spring alleviated Iowa’s prolonged drought but also resulted in considerable runoff to rivers, lakes, and streams. This contributed to sharp increases of E. coli and microcystin levels throughout the summer months, as well as concerning levels of nitrate in source waterbodies for municipal drinking water systems. These concerns were top of mind for Iowans and were an ever-present discussion in Weekly Water Watch, including an explainer of the public health impact of nitrates, findings from the Central Iowa Source Water Resource Assessment, and updates from the Iowa Water Quality Information System public map.  

Big figures from 2025: 

• Since IEC began tracking advisories in 2014, this year has had the highest number of state advisories, and 20 more advisories than the 2024 beach season. The record-breaking total was driven by the highest number of E. coli advisories. In the 15-week monitoring period for 40 public beaches, Iowa DNR issued 158 beach advisories for E. coli and 12 for microcystin. 
• 27 out of 40 state beaches had at least one advisory between Memorial Day to Labor Day. 
• Backbone Lake, Beeds Lake, and Lower Pine Lake Beach shared the most advisories for E. coli – 12 of the 15 weeks of the summer monitoring period. 
• While the number of microcystin advisories was below the annual average, Lake Darling Beach’s algal blooms worsened. For the third year in a row, Lake Darling had the worst overall beach health with ten E. coli advisories and six microcystin advisories. 
• As a recently added recreation site, advisories from Bobwhite State Park were not included in DNR’s weekly reports. However, the beach regularly exceeded safe E. coli levels with eight weeks of exceedances during the 15-week monitoring period. 
• In the same period, the U.S. Army Corps of Engineers Rock Island District issued 20 advisories for E. coli on the six beaches it monitors on Iowa reservoirs. The Corps will continue to release advisories for Saylorville, Red Rock, and Coralville reservoir beaches for another week. 

While the DNR monitors 40 state park beaches, there are countless city, county, and neighborhood water bodies that are not regularly tested for E. coli and microcystin. If your local waterway is not included in the DNR’s database, we recommend you contact the entity that oversees that waterway for current water and safety conditions. As always, report water that looks or smells unhealthy to your city, county, or to the Iowa DNR. Pollutant levels, including E. coli and microcystin, can change quickly, even within one day. Without adequate testing, Iowans are left without tools to protect themselves and their families.