Narrows/Day Island Marina is a saltwater beach in Pierce County, Washington. Across 242 bacteria samples collected between 2021 and 2025 at nearby monitoring stations, it earns a Beach Safety Grade of C — Fair.
About 10% of samples at Narrows/Day Island Marina exceeded the EPA Beach Action Value of 104 CFU/100 mL for Enterococcus — 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.
Narrows/Day Island Marina 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.