What is the water quality of the Hudson River?

Overall, our data show that most of the river is safe for swimming most of the time, but water quality is highly variable. Many tributaries, shorelines and areas near Combined Sewer Overflow (CSO) outfalls can remain unsafe for swimming for 2-3 days after rain.



In 2026, the water quality of the Hudson River is a complex tale of two halves. The Lower Hudson, which flows past New York City, has seen a massive recovery in terms of oxygen levels and bacteria, making it generally safe for secondary contact like kayaking and even "authorized" swimming events. However, it is still categorized as a Superfund site due to legacy industrial pollution. Specifically, the river bottom remains contaminated with PCBs (polychlorinated biphenyls) discharged by General Electric decades ago. While the water itself is much cleaner than it was in the 1970s, the toxins reside in the sediment and bioaccumulate in the wildlife. Because of this, the New York State Department of Health maintains strict fish consumption advisories; in many areas, women of childbearing age and children are advised not to eat any fish from the river at all. Rainfall also triggers "Combined Sewer Overflows" (CSOs), which can temporarily spike bacteria levels, so it is best to check real-time water quality monitors before any recreational contact.

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The short answer is “Yes!” The long answer is that it depends on when and where. Issues like sewage outflow and algal blooms keep many areas along the Hudson from being swimmable, particularly after rainfall.

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The “Salt Front” is the location where the river is 100 ppm salinity. 100 ppm salinity falls within acceptable drinking water standards.

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The Thames is considered to be the cleanest river in the world that flows through a major city. The Thames is home to 125 species of fish and more than 400 invertebrates.

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Saving the River's Fish. For schools of migratory shad, sturgeon, river herring, blue crab, menhaden and striped bass, the Hudson is an unimpeded corridor from the Atlantic to their ancestral spawning grounds.

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Men over 15 and women over 50 face fewer health risks from some chemicals. For that reason, they can eat up to six crabs a week from the Hudson River and New York City waters. Crabs from the Long Island Sound, Jamaica Bay and the ocean are less contaminated and are a better choice for everyone.

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For Your Health- In 1976, the Upper Hudson River was closed to fishing due to extremely high amounts of polychlorinated biphenyls (PCBs) in fish. These levels posed a high risk of possible harmful health effects in humans. Since 1976, the manufacture of PCBs has been banned and their use phased out.

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Predators like blue crabs and sturgeons do eat zebra mussels, but have never been shown to control natural populations. Research on new control measures, including biological controls, is ongoing, but the changes we've seen to the Hudson's ecosystem probably are irreversible or at least long-lasting.

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Geology. The Hudson is sometimes called, in geological terms, a drowned river. The rising sea levels after the retreat of the Wisconsin glaciation, the most recent ice age, have resulted in a marine incursion that drowned the coastal plain and brought salt water well above the mouth of the river.

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Seawater pushes into the Hudson and mixes with fresh water, making the river taste slightly salty. This mix of salt and fresh water is called brackish water.

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