Source Information
In Delaware, recreational water is monitored by the Department of Natural Resources and Environmental Control. Water samples are collected at least weekly at all guarded beaches during the swimming season (May to September). Water samples are analyzed to determine the levels of Enterococci bacteria.
Swim Guide checks for the latest information daily, Monday - Friday during the monitoring season. Please contact the Department of Natural Resources and Environmental Control (302-739-9939) during the off season if you would like to have the water tested before a special event.
A marine beach is marked Green when the single sample results show Enterococci counts below 104 cfu / 100ml of water AND when the geometric mean of 5 samples are fewer than 35 cfu of Enterococci per 100 ml of water. For fresh water beaches are marked GREEN when the E.coli counts are below 100 E.coli/100ml for a geomean AND below 185 E.coli/100ml for a single sample.
A marine beach is marked Red when single sample results show Enterococci counts above 104 cfu/ 100 ml of water or when the geometric mean of 5 samples is greater than 35 cfu of Enterococci / 100 ml of water. For fresh water beaches are marked RED when the E.coli counts are above 100 E.coli/100ml for a geomean OR above 185 E.coli/100ml for a single sample.
A beach is marked Grey when there is no current or reliable monitoring information available.
Results are posted online and on the 24-hour "Beach Hotline" at 1-800-922-WAVE.
Some Delaware beaches are subject to a permanent caution. Swimming in bays and inland waters, particularly after heavy rainfall, can have an elevated risk of illness due to high levels of contamination. Water quality may be better on the coast, and visitors to bay area beaches are urged to exercise caution.
