Portage County beaches are sampled for the presence of E coli bacteria throughout the swimming season from Memorial Day to Labor Day. In the event that bacteria levels are elevated above 235 cfu/100 ml, established by the U.S. Environmental Protection Agency as an increased health risk to swimmers, an advisory sign will be posted at that beach. Swimming is allowed, but caution is recommended. In the event that bacteria levels are at an unsafe level of 1,000 cfu/100 ml, a Beach Closure sign will be posted and swimming is not recommended.
Samples are tested the same day as collection by the University of Wisconsin - Stevens Point Water and Environmental Analysis Lab.
In the event that an advisory or closure sign is posted at the Portage County beach, that beach will be re-tested and the advisory or closure will be lifted once Ecoli bacteria levels are below the EPA standard of 235 cfu/100 ml.