New York City Department of Environmental Protection

About the Utility

The New York City Department of Environmental Protection (DEP) is a City agency that manages the New York City Water and Sewer System, supplying drinking water, treating the city's wastewater and running its drainage and stormwater programmes. The New York City Municipal Water Finance Authority finances capital improvements to the system, and the New York City Water Board proposes rates. DEP supplies approximately 1.1 billion gallons of drinking water each day to nearly 10 million residents, including 8.3 million in New York City. Its network serves all five boroughs through approximately 7,000 miles of water mains, tunnels and aqueducts and some 7,500 miles of sewer lines.

Water System

Upstate reservoir watersheds supply the system, with total available storage of 570 billion gallons. The Catskill/Delaware portion is delivered without filtration under Filtration Avoidance Determinations from the United States Environmental Protection Agency, maintained through source water protection programmes. The Delaware Aqueduct typically carries about half of the city's supply but leaks around 35 million gallons a day, and its final repair connection was paused in November 2024 because of drought. Average daily consumption was 1,102 mgd in FY 2025, including upstate and wholesale customers. That year water main breaks rose to 552, while main replacement slowed to approximately 13 miles.

Wastewater System

DEP's fourteen wastewater resource recovery facilities treat 1.2 billion gallons of wastewater daily. About 60% of the city is served by combined sewers, and because the plants cannot handle flows more than twice their design capacity, excess flows overflow through some 700 combined sewer outfalls. Overflow reduction proceeds under a consent order with the Department of Environmental Conservation, with green infrastructure complementing traditional grey investment. Effluent meeting federal and State discharge standards was 99.7% in FY 2025, a year in which sewer backup complaints fell to 7,345.

Investment & Priorities

Capital commitments reached $3.221 billion in FY 2025, the highest level since 2007. Rate-funded construction under way includes the Delaware Aqueduct repair, combined sewer overflow retention tanks for the Gowanus Canal and a comprehensive drainage system for Southeast Queens. A new Kensico-Eastview tunnel, required by a federal court consent decree, is due fully online by 2035. DEP spent $5.7 billion upgrading drainage over the last ten years and plans to invest more than $10 billion over the next decade.

Sustainability & Resilience

Extreme rainfall is a central climate risk. DEP has proposed raising the citywide drainage level of service, a standard under which more than 80 areas would require significant investment. DEP has built thousands of green infrastructure installations in the public right-of-way and manages Bluebelts. The Newtown Creek facility hosts the first co-digestion and gas-to-grid project at a wastewater facility in New York State, and DEP reports reaching the 40% greenhouse gas reduction that Local Law 97 requires of city government two years early.

Key Challenges

1. Completing the Delaware Aqueduct bypass connection, not expected until after 2027.
2. Maintaining approximately 7,000 miles of mains as breaks rose and replacement slowed in FY 2025.
3. Reducing combined sewer overflows where about 60% of sewers are combined.
4. Raising drainage protection in more than 80 priority areas.
5. Reducing reliance on estimated bills, which reached 17.5% of bills in FY 2025.

Major Projects