Old Olympic Highway Bridge, Oyster Bay is a saltwater beach in Thurston County, Washington. Across 48 bacteria samples collected between 2021 and 2022 at nearby monitoring stations, it earns a Beach Safety Grade of C — Fair.
About 8% of samples at Old Olympic Highway Bridge, Oyster Bay 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 sometimes crossed here over the monitored period. Bacteria samples occasionally exceed the safe-swimming threshold — check the latest advisory before swimming.
Read this grade as directional rather than settled: it rests on only 48 samples and has no results reported since 2022. That is enough to classify how the water has behaved, but not enough to separate this beach from another a grade away — a beach graded from thousands of samples at several stations is a firmer read. As more results are reported, the grade may shift.
Old Olympic Highway Bridge, Oyster Bay 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.