Sewer and stormwater pollution
Working to keep sewage and street pollution out of our waterways
The challenge
Failing infrastructure, and sewer systems that can’t handle rain
With the nation’s largest city at its mouth, and cities as distant as Glens Falls and Utica in its watershed, the Hudson River is home to millions of people across a vast geographical expanse. This densely populated area generates hundreds of millions of gallons of sewage each day, and its parking lots, rooftops, and roadways generate as much as 27,000 gallons of water per acre from a one-inch rainstorm.
The Clean Water Act — and, before it, New York’s Pure Waters Bond Act — played key roles in setting the goal of reducing and eliminating the impact of these pollution sources. But despite decades of improvements to collection and treatment infrastructure, sewage and stormwater remain the largest pollution source to the Hudson River Estuary, by volume, with some of its most negative impacts. Sewage treatment infrastructure is routinely overwhelmed during rainfall and extreme storms associated with climate change exacerbate the impacts, making finding solutions more challenging.
At its worst, this pollution can starve aquatic life of oxygen needed to survive, make water unsafe for recreation, and introduce chemical contaminants that are used in our homes or in industries that discharge their wastes to public sewers. These contaminants can include PFAS, pharmaceuticals, pesticides, microplastics and a range of other “micropollutants” that may be harmful alone or in combination. Stormwater, too, carries a range of contaminants, ranging from road salt to single-use plastic trash. Excess nutrients in sewage and stormwater can serve as fuel for harmful algae that produce toxins that put people, dogs and wildlife at risk. Floodwaters may carry a toxic stew of sewage and stormwater pollutants, as well as pollutants mobilized from hazardous waste sites. Untreated sewage is also a source of greenhouse gas emissions.
One of the most obvious and impactful sources of pollution are combined sewer overflows (CSOs). When sewers were built in many of our older cities and villages, they were designed to carry both toilet waste and street runoff in the same pipes, and these pipes were designed to overflow into our rivers when it rains. The points of discharge are CSOs. Their impacts often fall most heavily on cities and neighborhoods where low income, Black, indigenous and other people of color are burdened with other environmental hazards, and where the pollution prevents a robust healthy connection to water. Eliminating these raw sewage discharges is an expensive and often technically difficult task — and an important one to promote environmental justice.
Each year, New York City discharges more than 21 billion gallons of raw sewage from roughly 460 CSOs into local waterways when it rains. That’s enough to fill the Empire State Building 72 times. Dozens of other communities along the Hudson and its largest tributary, the Mohawk River, similarly rely on combined sewers, resulting in discharges of untreated or partially-treated sewage mixed with polluted stormwater.
21
billion gallons a year of untreated sewage is discharged from ~640 combined sewer pipes in New York City
1987
The last time New York City built a new wastewater treatment plant was in 1987
$2.26 B
needed for wastewater infrastructure upgrades in the Hudson Valley
410
locations monitored by Riverkeeper for sewage contamination
Upgrades to sewer infrastructure that reduce these overflows of raw sewage into the Hudson and its connected waterways — particularly from New York City, New Jersey communities, Westchester County and the Capital District — will be crucial to improving water quality.
- Focus areas
- Water qualityClimate impacts
What we're doing
Reducing sewage discharges
Riverkeeper has been fighting for years for major improvements to sewage infrastructure. We hold communities and regulators accountable for meeting the goals of the Clean Water Act, and we fight for state and federal funding, to ensure that the costs of reducing pollution don’t fall solely on local communities. Our water quality data help make the case for these investments, and we work alongside municipalities and community members to advocate for plans that commit to the infrastructure upgrades, policy changes and funding required to greatly reduce sewage and stormwater discharges into the Hudson and its connected waterways.
In response to a lawsuit by Riverkeeper and our partners, New York State has begun to to update water quality standards for waters around New York City. The critical test is whether the state will comply with the Clean Water Act to meet the goal of “swimmable” waters in our nation’s largest city.
Riverkeeper also provided comments and testimony to help shape New York City's PlaNYC, which has committed the city to eliminating sewage overflows by 2060. Since the city's current infrastructure construction plans don't match the goal, we continue to push for effective sewage discharge reduction methods, such as green infrastructure, storage tunnels and tanks, and treatment plant upgrades and the construction of a new treatment facility where the Rikers Island jail now sits.
Our water quality monitoring and advocacy for infrastructure upgrades and safe swimming and public access throughout the Hudson River watershed help drive awareness, building the groundswell of support necessary to enact the policies that keep our waters free of untreated sewage and street runoff.
All good science begins with a question, and the question that we began with was ‘How’s the water for swimming?’ There’s a belief at the core of that that people are going to care and steward the things they love and that bring them joy.
Sebastian Pillitteri
Community Science Manager
“Green infrastructure” and stormwater
“Green infrastructure” refers to soil and vegetative plantings such as green roofs that absorb stormwater on hard surfaces, preventing or slowing it from running into sewers and causing the system to overflow a mix of sewage and street pollution into local waterways.
Riverkeeper’s advocacy, in collaboration with partners and community members, leads to increased funding and more effective planning for New York City’s Green Infrastructure program, which is the largest in the United States. Riverkeeper published "Building an Equitably Green New York City" in 2022, providing actionable policy recommendations. New York City and State implemented some of them through their update to their Green Infrastructure Consent Order, and we continue to advocate for the remainder.
Riverkeeper also successfully advocates for legislation that provides incentives for property owners to plant green infrastructure and reduce stormwater runoff while ensuring that these benefits extend to small property owners in low income communities.
16x
more stormwater runoff from a one-acre parking lot than a one-acre meadow
$5.3M
Creating tree cover saved one city more than $5 million on residential energy use, runoff reduction, and air pollution removal in one year
Unified action in Westchester
Riverkeeper has been instrumental in forming and leading a coalition pushing for Westchester County and local governments to act effectively on issues including water pollution from sewers, flooding from stormwater, safe fishing and shellfishing, and increasing access to our waterfronts. The Westchester Coalition for Clean Water is calling for all waterways in Westchester to be clean and healthy, free of trash and sewage, and flood resilient by 2034.
Unifying the numerous Westchester sewer systems under county operation and maintenance would build an economy of scale and greater reliability, thus reducing discharges that — in Westchester alone — release over 1 of billion gallons of untreated sewage and polluted stormwater into the Hudson each year.
We are committed to working with county leadership and local governments to develop strategies to maximize historic levels of state and federal funding while prioritizing areas that are the most vulnerable and suffering from the worst sewage pollution.
Renewable Rikers
Replacing Rikers consolidated wastewater treatment plant on Rikers Island’s 413 acres would form the city’s cornerstone for sewage pollution reduction.The plant would restore local waters for fishing and swimming, and save the city hundreds of millions of dollars in wastewater treatment expenses. It could also house enough solar power and battery storage to shut down asthma-causing natural gas-fired peaker power plants in the Bronx and Queens.
We are part of the Renewable Rikers Coalition driving transformation of the island into a clean water and clean air hub — which necessitates closing the jail currently occupying the site and ending its history of violence, mistreatment, and deprivation of human rights for incarcerated individuals.
We believe the communities that have been most harmed by mass criminalization and environmental injustice should be the beneficiaries of a transition to a cleaner and greener future on Rikers Island.
Mike Dulong
Legal Program Director
Putting our waters on “pollution diets”
The Clean Water Act has several legally enforceable methods to improve water quality that is impaired by pollution. Riverkeeper advocates for robust implementation of the Clean Water Act and other environmental laws, including through CSO Long Term Control Plans (LTCPs), updated State Pollution Elimination Discharge System (SPDES) permits and the implementation of clean water plans, such as Total Maximum Daily Loads (TMDLs), which are often called “pollution diets.” Thanks in part to Riverkeeper’s advocacy, two of the Hudson’s largest tributaries, the Mohawk River and Wallkill River, are among the first large rivers to have TMDLs developed, and the plans are anticipated to include requirements to upgrade sewage treatment technology. Riverkeeper has advocated for strong CSO LTCPs in New York City and is monitoring their implementation in multiple river cities. Riverkeeper reviews dozens of SPDES permits each year and advocates for stronger discharge limits. The Clean Water Act set the goal of eliminating pollution discharges — by 1985 — and Riverkeeper continues to work toward this aspirational goal.
Investing in water infrastructure
Riverkeeper is a leader in the coalition effort with advocacy organizations, business, and legislators to establish the Water Infrastructure Improvement Act and Clean Water Infrastructure Act in New York State, pumping billions of dollars into grants for a range of water quality improvement projects. The largest investments from these landmark state spending programs have modernized sewage treatment plants, replaced aging pipes and pump stations, and reduced sewage overflows. Coupled with federal investments under the Bipartisan Infrastructure Law, these projects are reducing sewage impacts throughout the Hudson River watershed. Riverkeeper is also leading the effort to boost federal spending through the Water Resources Development Act (WRDA), starting with investments in the extensive and aging infrastructure along the Hudson’s largest tributary systems, the Mohawk River, Rondout Creek and Wallkill River.
Updates
Update
January 30, 2025
Keeping the pressure on for key state environmental funding
Event recap
December 19, 2024
Our effort to reduce pollution in Newtown Creek
Blog
December 4, 2024
Riverkeeper testifies on "forever chemicals" at NYS Assembly
Blog
July 29, 2024
House of Representatives passes Water Resources Development Act of 2024 with big wins for the Hudson and Mohawk watersheds
Press release
July 1, 2024
Clean water advocates and environmentalists announce the formation of the Westchester Coalition for Clean Water (WCCW)
Press release
October 18, 2023
With Release of New Water Quality Criteria, Riverkeeper and Save the Sound Challenge DEC to make NYC waters safe for swimming
Blog
July 14, 2023
Preparing for the next deluge
Blog
May 26, 2023
Will NYC waters ever be made consistently safe for swimming?
Related campaigns
Swimming and public access
Working to make it safe and free for everyone to swim in the Hudson
Water quality monitoring
Riverkeeper is the go-to source for information about the quality of the water along the Hudson River and its tributaries
Remediating and preventing contamination
Cleaning up decades of pollution and preventing more requires scientific understanding, targeted legal action, and sustained advocacy