Croton spillway

New York City drinking water

The water supply for 9.5 million New Yorkers depends on keeping our watersheds clean and protected

The challenge

Catskills
Access to clean drinking water is a human right. Impacts to our watersheds, such as sewage discharges, contaminated sites, urban run-off, harmful algal blooms, permitted discharges of water pollutants, and agricultural pollution threaten this right. By implementing sound watershed protection programs, we not only safeguard human health and aquatic life, but also provide economic benefit by reducing the need for costly water treatment upgrades.
New York City’s drinking water is sourced from reservoirs located north of the city in the Croton, Catskill, and Delaware watersheds. This system provides roughly 1 billion gallons of primarily unfiltered drinking water to residents each day through a 6,000-mile network of pipes and subterranean aqueducts.
The water is disinfected to kill bacteria and other pathogens, and treated to decrease the release of lead from household pipes. New York City’s Department of Environmental Protection continually monitors the water in both the reservoirs and the distribution system that carries water to residents’ homes.

9.5

million people — half the population of New York State — are served by the NYC water supply system, including much of Westchester and communities north

19

upstate reservoirs producing 1 billion gallons per day supply NYC’s drinking water 6,000 miles of pipes deliver drinking water from upstate reservoirs to NYC

Replacing aging infrastructure

Half a century ago, the city’s water supply was regarded as one of America’s proudest engineering accomplishments. But that same infrastructure is now in a state of disrepair that threatens its ability to continue to supply the city with water.
The New Croton Aqueduct, which stretches 31 miles from Westchester County to Manhattan, is over 100 years old, and its tunnels and shafts are in serious need of rehabilitation. New York City has begun construction on a new aqueduct from the Kensico Reservoir to Eastview Reservoir to improve flexibility in the water supply system.
The Delaware Aqueduct, which provides roughly 50 percent of the city’s water, is nearly 80 years old. Measuring 85 miles long, the aqueduct is the world’s longest tunnel — stretching from the Rondout Reservoir in Ulster County to New York City — and sections of it have been leaking millions of gallons of water a day for decades. Riverkeeper’s 2001 report, "Finger in the Dike, Head in the Sand," highlighted the need for a fix, which resulted in the construction now underway of a 2.5-mile-long bypass tunnel around leaks in the town of Newburgh and the town of Wawarsing in Ulster County.
The Catskill Aqueduct carries roughly 40 percent of the city’s water supply from the Ashokan Reservoir in Ulster County.
The level of federal funding for clean water infrastructure has dropped precipitously. We must prioritize investing in the repair, maintenance, and construction of these systems in order to ensure our communities continue to have access to clean, reliable and safe drinking water.

What we're doing

Through oversight, advocacy, and public outreach, we help protect drinking water from source to tap.

1997 Watershed Agreement

In 1997, Riverkeeper — alongside other key stakeholders — entered into an agreement to protect New York City’s unfiltered drinking water system, the Delaware and Catskill watersheds. The historic accomplishment provides the funding and oversight to address upgrade septic system, build and upgrade wastewater treatment systems, reduce agricultural and urban runoff and conserve large areas of forests that provide a natural filter. Through the agreement, Riverkeeper has a unique public role to ensure the protection of the drinking water system through oversight and regulation enforcement.

Drinking water source protection

Following the 1997 agreement, Riverkeeper has been instrumental in creating and strengthening existing protections throughout the watersheds that feed NYC’s drinking water supply.
In 2016, we began a Source Water Protection campaign to advocate for better protections statewide. That advocacy contributed to the historic enactment in 2017 of the $2.5 billion Clean Water Infrastructure Act, including over $100 million for a new source water protection land conservation program, legislation that expands drinking water protections for millions of New Yorkers, and the establishment of the NY State Drinking Water Source Protection Program.

2,000

square miles protected in the New York City drinking water watershed

Ashokan Reservoir: Stop the Mud

Halfway along its course through the Catskills, the Esopus Creek was dammed to create the Ashokan Reservoir, the unfiltered source of about 40 percent of New York City’s drinking water. Erosion from severe storms — which will become more common as the climate changes — causes excessive turbidity in the reservoir.
New York City managed this challenge by dumping massive amounts of muddy water from the reservoir into the Lower Esopus Creek, which flows into the Hudson. This solution allowed the state to preserve the quality of NYC drinking water, but in doing so it shifted costs and consequences onto farmers, businesses, communities, and wildlife downstream.
Riverkeeper has worked diligently as part of a coalition to “Stop the Mud,” pushing the state to find alternative solutions and to further analyze the effects of climate change on the management of the city’s water supply. In 2024, city and state officials agreed to avoid discharging visibly muddy water.
Following our huge win, with New York City committing to releasing cleaner water from the Ashokan Reservoir, Riverkeeper continues to work with our partners to ensure that water released from the reservoir is managed to promote ecological health and to mitigate flood risks.

Smart growth

One of the largest threats to New York City’s drinking water system is urban and agricultural runoff, which can contaminate reservoirs and watersheds with toxic pollutants.
To protect water quality and watershed communities, Riverkeeper actively participates in the environmental review process when developments are proposed in the watershed. We work hard to stop the most egregious project from being built and ensure that the environmental impacts of those that are built are minimized by advocating for reduced project size and use of progressive building technologies and practices.

Resources

NYC drinking water fact sheetNYS Drinking Source Water Protection ScorecardOpen Letter to NYS residents about Riverkeeper’s Source Water Protection Scorecard