There were 27 instances this summer when a single sample test for E. coli at a state beach came back above the state standard, but state regulators did not issue a swim advisory for the beach.
The Iowa Department of Natural Resources tests lake water at state park beaches for E. coli and cyanobacteria toxins from green-blue algae, weekly from Memorial Day weekend through Labor Day weekend. The department issues swim advisories when the tested samples are above a certain threshold.
The decision to issue a swim advisory is also weighed against a five-year data point that classifies beaches as “vulnerable” “transitional” or “less-vulnerable.” Beaches with a less-vulnerable classification do not receive “swimming is not recommended” advisories when a single E. coli test at the beach comes back higher than the state’s maximum standard for the bacteria…