Richmond has what’s called a Combined Sewage system; this means that the storm runoff drains and the sanitary sewer (human waste) share the same system. It also means that when the system is filled to over capacity- after a rain- the untreated contents of the combined system overflow into the James River, as seen in this diagram.
This is known as a Combined Sewage Overflow (CSO) event, and in Richmond, it happens nearly every time it rains, because our system is old and has not been updated with retention basins. There are 29 outflow locations where waste flows into the James during a CSO event.
Swimming in the James after a rain can expose you to harmful pathogens and toxins, including antbiotic-resistant staph infections. This counts for your pets, as well; keep the dogs out of the water if a CSO event has recently occurred.
You can sign up for e-mail notifications of CSO events here. Because rain washes surface contaminants, like pesticides, fertilizer, and oil into nearby bodies of water, it’s not a good idea to swim after a rain even in areas that don’t have Combined Sewers.