The Hudson River sparkled from the lights of New York City's skyline when a group of open water swimmers first arrived at Pier 25 on a recent morning. The sun was barely peeking through the clouds and fog when they boarded a motor boat, the Melissa Marie, which would accompany the four swimmers as they circumnavigated Manhattan.
Just over eight hours and nearly 29 miles later, the proud and pruney relay team crossed the finish line, a tall wooden piling on a dock just off Battery Park.
“We thought we were gonna have high winds and bad weather, but it just got better and better,” said Derek Yach, a cancer survivor who initiated the swim as a fundraiser for cancer treatment equipment in Kenya. Seeing the sights of Manhattan from the water, he said, is “just spectacular.”
While most New Yorkers might shudder at the thought of swimming in the waterways surrounding the city, these swimmers are part of a growing group advocating for increased access to the harbor, buoyed in part by improved water quality and, perhaps, nerve.
Swimmer prepare to enter the Hudson River at Pier 25 in the early morning.
According to the city’s Department of Environmental Protection, on average, bacteria in water samples across the Hudson and East rivers test well within the state’s standards for swimming, due in part to river revitalization efforts that have been ongoing since the 1970s.
Still, some oceanographers and city officials have mixed feelings about swimming in the heavily trafficked waterways. A spokesperson for the city’s Department of Health and Mental Hygiene told Gothamist that New Yorkers should celebrate the improving water quality but recommended swimming at the ocean beaches instead.
An open water swimmer with the Statue of Liberty in the background.
But the team at URBANSWIM, an organization that coordinates open water swims around New York, including last week’s circumnavigation, is adamant that swimming in the harbor is safe when it’s done right.
“The waterways belong to all of us,” said Deanne Draeger, the cofounder of URBANSWIM, which helped nearly 200 people swim in the harbor this year. “The water shouldn't be just a view. It’s a public space.”
Dead rats and more
Mary Money, one of the relay team members, recalls swimming past a dead rat in the Harlem River on a previous swim.
Draeger said “Coney Island whitefish” — local slang for condoms — also make occasional appearances. And Gerry Louw, URBANSWIM’s other founder, admitted that he once arrived at Pier 25, where the Melissa Marie docked, only to find the police investigating a dead body in the water.
The Hudson River near Chambers Street.
But data shows that the harbor is the cleanest it has been in more than a century, and continues to improve, according to the city.
John Waldman, a biology professor at Queens College who researches New York harbor, said that 100 years ago, the city sent raw, untreated sewage straight into the riverways.
Near outfalls, there was known to be 10 feet of straight sewage steaming and bubbling in the harbor, “decaying before your eyes,” Waldman said.
Waldman said he remembers driving down FDR Drive in the 1970s “and seeing turds in the water.” Today, he said, that would be a rarity.
The Clean Water Act of 1972 dramatically improved water quality in New York and nationwide, environmentalists say. The landmark law provided a framework for regulating water pollution and improving water quality in public waterways. It also set a goal of making all waters clean enough to swim and fish in by 1983.
Mary Money aboard the Melissa Marie.
While that has yet to be universally achieved, environmentalists in New York say that benchmark should remain.
Earlier this month, the Trump administration moved to narrow the definition of what is considered “waters of the United States” to strip protections from wetlands, which act as natural water filters, removing pollutants and sentiment before they reach the Hudson and other waterways.
But what about the water quality?
Scientists track all sorts of data points in New York City harbors, including algae, oxygen, and temperature changes. But the most important measure of whether water is safe enough for swimming is called fecal indicator bacteria, according to Andrew Juhl, a biological oceanographer at Columbia University’s Lamont-Doherty Earth Observatory.
Juhl puts it delicately. This type of bacteria does not naturally occur in our waterways — it's found naturally “in the guts of warm-blooded animals like ourselves,” he said. When it’s found in the open water, it indicates sewage contamination, Juhl said.
Four relay swimmers in the water.
After a major rainstorm, an influx of street runoff can overflow the city’s sewage system, Juhl said. The mixture of sewage and runoff — full of whatever grime the city holds on that given day — overflows directly into the river at hundreds of different discharge points.
Juhl said that swimming in sewage-contaminated water can make you sick — most commonly with nausea, diarrhea, or something like an ear infection or a rash.
When bacteria levels are high enough, he said, the risk of what you could theoretically catch is, “I mean, sky's the limit, right?” Juhl said.
But most of the time, he added, the water quality is good enough where that’s not an issue.
Juhl worked with Riverkeeper, an organization that advocates for the city’s waterways and tracks its quality, for more than 15 years, until 2022.
While he was there, Juhl said, fecal indicator bacteria in water samples across the city tested safe enough to swim roughly 80% of the time.
Water quality varied depending on the day and location, Juhl said, but bacteria levels stayed relatively consistent over the past 20 years and spiked when it stormed.
Juhl said this may have been the case this past year, which, according to Riverkeeper, saw higher levels of bacteria. Water samples across the city passed swimming standards about 60% of the time between May 2025 and this August.
Deanne Draeger, co-founder of URBANSWIM.
Draeger said she keeps a close eye on the weather to make sure the conditions are safe before anyone hops in. At this point, thousands of people have participated in one of her organization’s New York City open water swims.
None of them, she said, has reported getting sick from a swim, and neither has she.
(The relay swimmers Gothamist interviewed said they have never gotten sick from open water swims. Yach, who has survived two types of cancer, said open water swims have helped him get healthy.)
Swimmers Leila Shields and Derek Yach in waters off of Manhattan.
Juhl said he himself wouldn’t swim in the surrounding harbors, and anecdotally, he has heard various health complaints from those who have. But two other scientists who study water quality said that they would swim in the river, so long as there hasn’t been a recent overflow of sewage.
“ This is not a risk-free activity,” said Mike McCann, a researcher and ecologist at the Billion Oyster Project, an organization that is working to restore the harbor by replenishing its oyster reefs. “But we can now judge what is the appropriate level of risk to do these really fun and rewarding and special activities.”
”There's a large number of us that are hardy and dedicated and willing to do it,” McCann said. “And, you know, you take a shower afterwards.”
Before diving in
Those who swim the harbor say it is not for the faint of heart. While one can technically swim in most parts of the Hudson River, there are no public swimming access points in New York City, according to Riverkeeper.
That means jumping in the water requires tackling some logistical hurdles.
Last week’s swims, Draeger said, required coordinating with the Coast Guard and the NYPD to make sure other boats were aware they were sharing the waters with swimmers.
The swims also require a trailing motor boat; a paddler in a neon kayak to guide the swimmer; wearing a neon swim cap for visibility; and the careful attention of a safety coordinator, who keeps a close eye on the river ahead, Draeger said.
“It's kind of like a cocoon around the swimmer,” Draeger said. “ A little pod out there on the water keeping the swimmer safe.”
Draeger adds it isn’t a good idea to jump in the water without such safety precautions, noting the currents and tides are strong. “That can be very potentially dangerous if it's something you don't understand,” she said.
Your city, your water
The swimmers are hardly alone. As the water continues to improve, the harbor is home to increasing amounts of marine life. Whales of New York tracks the presence of whales near New York Harbor by using acoustic monitoring technology. Two were spotted in the area this month alone.
Seeing a sea turtle, a dolphin or a stingray would not be out of the question either, scientists say, although jellyfish or large schools of fish would be much more common.
The city's Department of Environmental Protection said in a statement that “the return of these animals shows that our investments in water treatment and management have produced dividends in the increased health and robustness of New York’s marine ecosystem.”
Swimmers, from left to right, Keith Kirkpatrick, Mary Money, Leila Shields and Derek Yach.
Still, Juhl said, the harbor’s marine life would be “the least of my worries” if he was swimming in the Hudson: “I'd be way more worried about human-powered vehicles than whales or dolphins or sharks.”
URBANSWIM is continuing to coordinate around those vehicles for another open water swim event this Saturday, its last of the season. Thirty people signed up to swim in remembrance of 9/11, in a trek between the tip of Manhattan to the Statue of Liberty, with some beginning at the former and others the latter.
Draeger called the swim a celebration of resilience, not unlike the river itself.
"The story of the Hudson River over the last couple of decades is an environmental success story. It really is,” Juhl said.
“It has gotten so much better, and that's a really good reason to keep pushing,” Juhl said. “Because they could get even better.”
And Draeger said she sees this effort as increasingly important as climate change continues.
“I think as our planet warms and conditions get warmer here in New York City, it's gonna become critical that we have access to our waterways for swimming, for cooling,” Draeger said.
The harbor, she said, is part of our city.
“It belongs to the people.”
