Harbor Island Beach is a saltwater beach in Westchester County, New York. Across 226 bacteria samples collected between 2022 and 2024 at nearby monitoring stations, it earns a Beach Safety Grade of F — Failing.
About 82% of samples at Harbor Island 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 exceed the safe-swimming threshold a large share of the time — this beach flags advisories often.
The evidence behind this grade is deep for a beach page: 226 results from 11 monitoring stations, spanning 2022 to 2024. Enough sampling, from enough places, over enough seasons that one bad week can't drive the letter.
Harbor Island 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.