An analysis of bacteria sampling data from beaches in 29 coastal and Great Lakes states and Puerto Rico reveals that 2,580 beach sites – more than half of all sites tested – were potentially unsafe for swimming on at least one day in 2018, and 546 sites were potentially unsafe at least 25 percent of the days that sampling took place. Sites were considered potentially unsafe if bacteria levels exceeded the U.S. Environmental Protection Agency’s most protective “Beach Action Value” thresholds, which the EPA suggests states use as a “conservative, precautionary tool for making beach notification decisions,” and are associated with an estimated illness rate of 32 per 1,000 swimmers. (Many states use other thresholds for beach closure and advisory decisions. Therefore, results presented in this report may differ from state reports on beach water quality.) (See Methodology for details.)
