Atwater Park Beach is a Great Lakes beach in Milwaukee County, Wisconsin. Across 146 bacteria samples collected between 2021 and 2025 at nearby monitoring stations, it earns a Beach Safety Grade of B — Good.
About 4% of samples at Atwater Park Beach exceeded the EPA Beach Action Value of 235 CFU/100 mL for Escherichia coli — the threshold at which water managers typically post a swimming advisory. In practice that means the safe-swimming limit was rarely crossed here over the monitored period. Bacteria samples rarely exceed the safe-swimming threshold.
The evidence behind this grade is deep for a beach page: 146 results from 2 monitoring stations, spanning 2021 to 2025. Enough sampling, from enough places, over enough seasons that one bad week can't drive the letter.
Atwater Park Beach was not under a swimming advisory in the most recent EPA snapshot. Conditions can change quickly after heavy rain or high runoff, so it's still worth checking the current advisory the day you go.