Chesapeake Bay Foundation

Source Information

The Anne Arundel County Department of Health collects water samples from Memorial Day - Labour Day. The water is tested for enterococci, bacteria found in the intestine of all warm-blooded animals. Swim Guide checks for the latest information daily, Monday - Friday during the swimming season. A beach is marked Green when there is less than 104 MPN (Most Probable Number) colonies of Enterococci / 100 ml of water for bodies of water that are sampled weekly or bi-weekly and 158 MPN colonies / 100 ml of water for bodies of water that are tested monthly. A beach is marked Red when there are more than 104 MPN colonies / 100 ml of water for beaches that are tested weekly or bi-weekly and 158 MPN colonies / 100 ml of water for bodies of water that are tested monthly. A beach will also be posted if results from an area that has been resampled 5 times due to high levels of bacteria come back with results over 35 MPN colonies / 100 ml of water. A beach is marked Grey when there is no current or reliable monitoring information available. Maryland Healthy Beaches notification system has partnered with Google Earth to send updates. However, Swim Guide prefers to contact the Health Department directly as we are unable to determine the monitoring schedule Google Earth uses. The Anne Arundel Department of Health operates a 24-hour automated test results phone line at 410-222-7999. A “no direct water contact” advisory is placed on beaches for 48 hours after a heavy rainfall, however the Anne Arundel County Department of Health’s website and The Maryland Healthy Beaches website are not updated.