Grant Park Beach is a Great Lakes beach in Milwaukee County, Wisconsin. Across 709 bacteria samples collected between 2021 and 2025 at nearby monitoring stations, it earns a Beach Safety Grade of D — Poor.
About 18% of samples at Grant 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 frequently crossed here over the monitored period. Bacteria samples frequently exceed the safe-swimming threshold; swimming advisories are common here.
The evidence behind this grade is deep for a beach page: 709 results from 20 monitoring stations, spanning 2021 to 2025. Enough sampling, from enough places, over enough seasons that one bad week can't drive the letter.
Grant 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.