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No swimming 48 hours after a rainstorm

The Chesapeake Bay, Severn River
The Chesapeake Bay, Severn River
Picture taken by Stephanie Siemek

Boating, fishing, crabbing, and swimming are just a few recreational activities many Marylanders enjoy during the summer. It is one of the perks of living so close to multiple water sources; however, how many of us are familiar with the 48-hour rule?

Residents should avoid swimming in any natural waters 48 hours after a rainstorm that produced ½ inch or more of rain. This is due to the amount of bacterial levels that are drawn into the water from the stormwater runoff. Warm-blooded animals are the source of Enterococci, normal bacteria found in the intestines of humans and animals; therefore, wildlife and pet waste and failing septic tanks all contribute to this problem.

According to The Chesapeake Bay Foundation, “the acceptable level of enterococci bacteria is 104 bacteria colonies per 100 milliliters of water”. The levels that are typically seen in the Severn are around 300; the Magothy River, from 100 to 1,000; and South River, from 100 to almost 400. You may find more information about the amount of bacteria found in your local waters by visiting Dr. Sally Hornor’s website. The South River Federation, Dr. Sally Horner of Anne Arundel Community College, and Riverkeeper Diana Muller have been working together in order to monitor bacterial counts after rainstorms in swimming/ recreational areas through a program called Operation Clearwater – South River.

Therefore, if you have a septic tank make sure it is up to par and there is no leakage. Furthermore, clean up after your pet! They are a huge contributor to these bacteria and during each rainstorm their waste is washed into any nearby stormwater drain, creek, river, etc.

If you decide to be bold and swim in the water within 48 hours accidentally ingesting the water may cause an upset stomach and if you have any open wounds, they have the potential to get infected. The Chesapeake Bay provides many recreational activities; therefore, let’s start taking care of it so that the 48-hour rule no longer needs to be implemented.