ARI SHAPIRO, HOST:
In cities around the U.S., swimmers have started to tip toe back into waters that have been off limits for decades because of pollution. Here in Washington, D.C., a bright green mat of algae used to clog the Potomac River each summer. In fact, it's been illegal to swim in any D.C. waterway since the early 1970s. Now, after years of cleanup efforts, city officials are starting to rethink that swim ban. Jacob Fenston reports from member station WAMU.
JACOB FENSTON, BYLINE: Picture this - it's one of the hottest days of the year; heat index - 107. You're lounging by a slow-moving river, feet dangling in the water.
JEFFREY MATTHEWS: It's so relaxing out here. I could just sit here all day.
FENSTON: Jeffrey Matthews is watching his two young kids splash around in the shallow water but not in the river. They're in a fountain a few steps from the Anacostia River itself.
Would you ever swim in the Anacostia?
MATTHEWS: I don't think so (laughter).
FENSTON: Generations of D.C. parents have told their kids to stay away from the Anacostia River.
ERIN GARNAAS-HOLMES: It's been the poster child for a degraded urban waterway for decades.
FENSTON: Erin Garnaas-Holmes works for the nonprofit Clean Water Fund. And he says there are two obstacles to swimming in the Anacostia.
GARNAAS-HOLMES: One is the technical challenge of making sure that the water is actually clean enough.
FENSTON: That, he says, is actually easier than the other big challenge.
GARNAAS-HOLMES: Convincing people that we're actually getting towards a space where you can stick your hand in and pull it out and there will be more than just the skeleton left.
FENSTON: Washington, D.C., is one of 700 cities around the country where antiquated sewer systems regularly overflow into nearby waterways when it rains. But in the Anacostia, there's a lot less sewage than there used to be. An upgraded sewer system is now preventing 80% of sewage overflows. A similar upgrade is in the works for the Potomac. And for the first time in many years, people are starting to ask what swimming could look like in D.C.'s rivers.
MERRILL ST LEGER: So you could have a large lap pool, for instance. You could have just a general swim area.
FENSTON: Merrill St. Leger is an urban planner. She calls this a river pool and says cities all over the world are building them in formerly polluted urban waters.
ST LEGER: Copenhagen has a number of really interesting examples of harbor baths.
FENSTON: St. Leger visited four of them last summer and brought back photos - platforms in the middle of the Danish capital packed with swimmers and sunbathers. There are similar examples in Paris and Zurich, and there are plans in the works in London, Boston and New York City. In Washington, city officials are on board. Tommy Wells is director of the District Department of Energy and Environment.
TOMMY WELLS: I believe we will have swimming platforms in Washington, D.C., no later than 2025.
FENSTON: And people are already getting in the water. On a recent evening, a dozen or so swimmers lined up on a dock and jumped into the light green Potomac.
ELVERT GARDNER: I was initially worried about swimming in the Potomac. I figured that I was going to jump out of the water and my skin was going to fall off or something like that.
FENSTON: Elvert Gardner's a triathlete. This group has been swimming in the Potomac weekly for the past decade just outside the D.C. border where swimming isn't officially banned. So how's the water?
GARDNER: I have been in water far nastier than this.
FENSTON: Within the city's borders, officials have been inching away from the swim ban. Now it's possible to get a special permit for swim events. Erin Garnaas-Holmes says he's been thinking about applying for one on the Anacostia.
GARNAAS-HOLMES: Where we have a swim day in the river, maybe jump off of a dock and test it out.
FENSTON: And Portland, Ore., started opening swimming beaches on the Willamette River in 2014. Washington could be next with its first swim days as soon as next summer.
For NPR News, I'm Jacob Fenston. Transcript provided by NPR, Copyright NPR.