16 Iowa beaches unsafe for swimming as E. coli spikes during heat wave

Iowa families heading to the water this weekend should check before they wade in. The Iowa Department of Natural Resources has posted a season-high 16 beaches as not recommended for swimming due to elevated bacteria levels.

The latest weekly report, released July 31, shows a sharp increase in water quality advisories across the state. That is three more beaches than the previous week and the highest number since the 2026 swimming season began on Memorial Day weekend.

State officials test 41 public swimming beaches every week from late May through Labor Day. They look for E. coli bacteria and harmful algae that can cause illness in swimmers. The DNR updates its findings each week on its website and by phone at (515) 725-3434.

Which Iowa beaches have swimming advisories?

The DNR lists 16 state park beaches as unsafe for swimming this week. Most are classified as vulnerable, meaning they have a history of exceeding bacteria limits in recent years.

Here are the beaches with advisories and their test results as of late July:

• Backbone Beach (Vulnerable) – Exceeded single-sample and five-sample Geomean limits for E. coli
• Beeds Lake Beach (Vulnerable) – Exceeded single-sample and five-sample Geomean limits
• Big Creek Beach (Less vulnerable) – Exceeded five-sample Geomean standard
• Black Hawk Beach (Less vulnerable) – Exceeded five-sample Geomean standard
• Bobwhite State Park (Not available) – Exceeded single-sample limit for E. coli
• Clear Lake State Park Beach (Less vulnerable) – Exceeded both limits
• Crandalls Beach (Less vulnerable) – Exceeded single-sample limit
• Denison Beach (Less vulnerable) – Exceeded five-sample Geomean standard
• Emerson Bay Beach (Vulnerable) – Exceeded five-sample Geomean standard
• George Wyth Beach (Vulnerable) – Exceeded both limits
• Lake Darling Beach (Vulnerable) – Exceeded five-sample Geomean standard and algal toxin action level
• Lake Manawa Beach (Vulnerable) – Exceeded both limits
• McIntosh Woods Beach (Vulnerable) – Exceeded both limits
• Nine Eagles Beach (Vulnerable) – Exceeded both limits
• Prairie Rose Beach (Vulnerable) – Exceeded both limits
• Union Grove Beach (Vulnerable) – Exceeded five-sample Geomean standard

What about city and county beaches?

The DNR also tracks 39 city and county beaches across Iowa. This week, 10 of those reported E. coli levels above the single-sample limit. In the Des Moines metro, that includes Blue Heron Lake at Raccoon River Park in West Des Moines and Hickory Grove Park Beach in Story County.

Are any beaches improving?

No. All 13 beaches listed as not recommended in the July 24 report maintained that rating this week. There have been no improvements since the previous advisory.

What about beaches with special statuses?

Three state beaches have additional restrictions or closures:

• Blue Lake Beach at Lewis and Clark State Park remains closed due to low water levels. The DNR is not testing while it is closed.
• Brushy Creek Beach has suspended monitoring because of construction.
• Lake Keomah has suspended monitoring due to low water. The DNR drained the lake in July 2024 for a major renovation and water quality project that was expected to last through spring 2026. The DNR warns people to stay out of the lake bed, which may look dry but is soft and could quickly entrap people.

How does the DNR classify beach safety?

The DNR sorts state park beaches into three categories each year based on recent bacteria history:

• Vulnerable: The beach exceeded the geometric mean standard in three or more of the last five sampling seasons.
• Transitional: The beach exceeded the standard in two or fewer of the last five seasons but was previously classified as vulnerable.
• Less vulnerable: The beach exceeded the standard in two or fewer of the last five seasons and was previously classified as transitional or less vulnerable.

This week, 10 of the 16 beaches with advisories are classified as vulnerable, indicating a persistent water quality problem at popular recreation spots.

What should Iowa families do?

Before heading to the beach, check the DNR's latest report online or call (515) 725-3434. Avoid swimming at any beach with an advisory, especially for young children, the elderly, and people with weakened immune systems. The DNR recommends showering after swimming and avoiding swallowing lake water.

For the full list of advisories, visit the Iowa DNR beach monitoring website.