The National Resources Defense Council (NRDC) prepares an annual analysis of water quality and public notification data at coastal U.S. beaches. The 2013 Report found that the number of beach closing and advisory days decreased 14 percent from 2011, due in large measure to the drier beach season. More than 80 percent of closings and advisories were issued because bacteria levels in beach water
exceeded public health standards, indicating the potential presence of human or animal waste in the water.
For more information and a copy of the 2013 NRDC "Testing the Waters" report, see:
http://static-lobbytools.s3.amazonaws.com/press/58172_nrdc_2013_testing_the_waters_report.pdf