Every Thursday evening and Sunday morning in the spring and summer, between 40 and 80 swimmers plunge into the Potomac River to practice open water swimming. But just a few miles away, swimming in the Potomac and Anacostia rivers in Washington, D.C. has been banned for the last 50 years.
These open water swims are held off National Harbor in Oxon Hill, Maryland, by the organization WaveOne Open Water and allow triathletes and swimmers the chance to practice outside of a pool. Denis Crean, WaveOne founder, started the organization in 2009 to give people a place to swim safely in the area. Crean has been a lifelong swimmer and said he loves open water events.
"There's nothing like being able to jump in and just go straight for a mile or two and then turn around and come back,” Crean said.
The Potomac Riverkeeper Network (PRKN), a nonprofit organization that serves as the voice of the river, has been working to improve water quality and are pushing to end the District’s swim ban through their “Swimmable Potomac Campaign.”
And with four years of water quality monitoring showing places with consistently clean water, swimming in D.C. again could be on the horizon.
A history of pollution
The Potomac River is the second largest tributary of the Chesapeake Bay behind the Susquehanna, stretching 380 miles from the headwaters in West Virginia to the Bay, and runs through Washington, D.C.
According to a timeline compiled by the Interstate Commission on the Potomac River Basin (ICPRB), when John Smith first arrived in 1608, he described the Potomac as having plentiful fish and animals such as otters and beavers swimming in it. As the population grew in the 14,700 square mile watershed, more and more pollutants flowed into the Potomac.
Almost 300 years later, in 1894, the river was reported to have too much sediment and bacteria to swim in at certain times during the year. In 1957, following several decades of untreated wastewater flowing into the rivers, in addition to significant land development, the U.S. Public Health Service declared swimming in the Potomac River unsafe. In 1971, swimming or wading in the Potomac, Anacostia and Rock Creek was officially banned in the district.
In response to situations such as the ailing Potomac River, the Clean Water Act (CWA) was signed in 1972 with the goal of creating fishable, swimmable water for all Americans. The CWA was the first major U.S. law to address water pollution, created standards to regulate pollutant discharges coming into waterways and spurred a variety of conservation projects along the Potomac.
The CWA set wastewater standards and made it illegal to discharge any pollutant from a point source into navigable waters without a permit. This year marks the 50th anniversary of the CWA.
Potomac Riverkeeper Dean Naujoks is leading the Swimmable Potomac Campaign and said that in the early 1900s over 20,000 people a day would swim in the Tidal Basin. Other places in the city used to have areas in which to access the water, such as Arlington Beach where the 14th Street Bridge currently stands.
“There used to be a lot of people that swam in the Potomac River and that is an existing or designated use that should be protected,” Naujoks said. “We've continuously made the argument that we want the swim ban lifted.”
To improve water quality, the PRKN helped push through a law that requires the City of Alexandria to stop 95% of its raw sewage discharges into the Potomac River by 2025. The city had previously been dumping over 70 million gallons of raw sewage and polluted stormwater into the river annually, causing sewage overflows to occur when it rained. Washington, D.C. also has a court-ordered requirement to reduce raw sewage discharges by 96% by 2030 through the District's Clean Rivers Project.
Collecting data to help their cause
In an effort to determine where swimming could safely occur, the PRKN has been collecting consistent water quality data from May to October each year since 2019. With the help of 75 volunteers who collect weekly water samples as a part of the organization’s community science water quality monitoring program, 18 sites are tested along the Potomac in D.C., Maryland and Virginia.
Naujoks said that when he started his job seven years ago people would ask him if the water was clean and found he had little water quality data to look at to provide an answer.
“I was stunned that there was so little data,” Naujoks said. “[The water quality monitoring program] has helped me tremendously … it's just given me a much better understanding of the river. Now we have three years of data at a lot of these sampling locations and can see where it's safe to swim and where it's not.”
The Anacostia Riverkeeper has also been testing water quality since 2019 in D.C. and Maryland in the Anacostia River which flows into the Potomac. They have roughly 80 fully certified volunteers who test the water every week in the district.
Christine Burns, Anacostia Riverkeeper watershed program manager, said having community scientists collect water samples is a way to expand the reach of small organizations that are working to improve water quality.
“With community science you can have people out throughout your watershed all at the same time on the same day getting data which is pretty incredible,” Burns said. “It gives a really nice snapshot every week of what's going on.”
PRKN water quality samples are collected every Wednesday morning and brought to their “floating lab” which is a boat called the Sea Dog where they are tested. By Thursday evening, data is published to an app and website called Swim Guide where people can look up water quality conditions in areas near them for the weekend.
In the last two years, over 52,000 people have used Swim Guide to find whether or not it's safe to be in the Potomac.
Crean said WaveOne is always looking at water quality when hosting weekly swims or larger open water races. He works with the D.C. Department of Energy and Environment and the Anacostia and Potomac Riverkeepers to ensure waters are safe to swim in.
“Water quality is a moving target,” Crean said. “Anytime that you're in a natural circumstance and in our case, it's natural water, there's a lot of variability. On a normal day or week, [water quality] is fine, just like you would jump into any lake, but then you have certain rain events where there's going to be runoff, so we're careful about that.”
The PRKN published a Swimmable Potomac Report in 2022 with data from all their testing sites. The results show that water quality is improving in many places. The tests look at air and water temperature, pH, turbidity and bacteria levels.