Long Island Water Distribution and Local Water Providers
On Long Island, drinking water comes from underground aquifers, a vital natural resource that requires careful management and protection. Depending on where you live, water service may be provided by a countywide authority, a municipal district, or a smaller local system. Below is a practical overview of how service is organized across Nassau and Suffolk Counties.
Because district boundaries can be very specific, the exact provider for a home or business may depend on the street address rather than the broader town name. If you are unsure, check your water bill, municipal records, or the provider’s official website before making service or billing inquiries.
Suffolk County Water Authority (SCWA)
The Suffolk County Water Authority (SCWA) is the largest water supplier on Long Island, serving most of Suffolk County and supplying water to well over a million residents. Operating as a public-benefit corporation, SCWA is a not-for-profit utility, with revenue reinvested into infrastructure, treatment, system maintenance, and aquifer protection.
SCWA is also one of the largest groundwater suppliers in the United States, with an extensive network of wells, storage facilities, treatment systems, and distribution mains. Service details, projects, and water quality updates may change over time, so residents should check directly with SCWA for current information.
Water Authority of Western Nassau County (WAWNC)
In Nassau County, the Water Authority of Western Nassau County (WAWNC) provides public water service across a substantial portion of western Nassau. This public authority operates wells, treatment facilities, and distribution infrastructure to support households, businesses, and other local users in its service area.
As with other Long Island providers, coverage boundaries and customer service procedures can vary by community, so it is best to confirm your address with the authority if you are moving, opening an account, or researching water quality information.
Water Authority of North Shore (WANS)
On Nassau’s North Shore, some communities have been part of an ongoing shift from private water service toward public ownership. The Water Authority of North Shore (WANS) was created to bring certain local systems under public control, with the goal of greater accountability and long-term investment in water infrastructure.
Communities associated with this transition include Sea Cliff, Glen Head, Glenwood Landing, Roslyn Harbor, and nearby areas. Because service arrangements can evolve as projects and transfers move forward, residents should check the official authority website for the most current status by address.
Local Water Districts in Nassau County
Beyond the larger authorities, Nassau County also has many local water districts and village-operated systems, each responsible for specific neighborhoods or municipalities. These systems often maintain interconnections with neighboring districts to help with redundancy, maintenance, and emergency supply needs.
Some of the better-known districts include:
- Manhasset–Lakeville Water District – Serving Manhasset, Lake Success, and parts of Flower Hill and Plandome Heights.
- Port Washington Water District – Covering Port Washington, Baxter Estates, Manorhaven, and nearby communities.
- Roslyn Water District – Serving Roslyn, Roslyn Estates, and parts of East Hills, Flower Hill, and Port Washington.
- Garden City Park Water District – Serving Garden City Park, parts of Mineola, and surrounding areas.
- Jericho Water District – One of Nassau’s larger districts, serving Jericho, Syosset, Brookville, Muttontown, and parts of Oyster Bay.
- Hicksville Water District – Serving Hicksville and parts of Levittown, Plainview, and East Meadow.
These districts provide local points of contact for billing, annual water quality reports, conservation programs, and service notifications. Some Nassau communities have historically been served by private utilities, and arrangements in a few areas continue to change, so address-level verification is still the safest way to confirm your provider.
Nassau County’s water-service map remains one of the most fragmented on Long Island, with dozens of separate districts, authorities, and village systems operating side by side.
Town & Village-run Districts in Suffolk County
While the Suffolk County Water Authority supplies most homes and businesses, several towns, villages, and independent districts operate their own systems. These providers manage wells, treatment facilities, and distribution lines for their specific communities, giving residents a local contact for billing, water quality information, and service concerns.
Notable Suffolk water districts include:
- Riverhead Water District – Serving Riverhead and nearby hamlets, including residential, business, and agricultural users.
- South Huntington Water District – Covering parts of Huntington, including South Huntington and Melville.
- Greenlawn Water District – Serving Greenlawn and surrounding portions of the Huntington area.
- Hampton Bays Water District – A Town of Southampton water district serving the Hampton Bays area.
Although smaller than SCWA, these systems are important local providers and, like all Long Island water suppliers, they must balance reliable service with ongoing aquifer protection and infrastructure upkeep.
Oversight and Regulation
Water distribution on Long Island is overseen through a mix of public-health regulation, environmental review, and utility governance.
- In Suffolk County, the Suffolk County Department of Health Services monitors community water systems for compliance with drinking water standards, alongside applicable New York State requirements.
- In Nassau County, the Nassau County Department of Health oversees public-health compliance for community water systems, while the New York State Public Service Commission regulates rates and service standards for investor-owned utilities.
- Most providers also publish annual water quality reports, sometimes called consumer confidence reports, which are the best source for current testing, treatment, and system updates.
| Region | Primary Providers | Example Local Districts |
|---|---|---|
| Suffolk County | SCWA plus several town-, village-, and district-run systems | Riverhead, South Huntington, Greenlawn, Hampton Bays |
| Nassau County | WAWNC, WANS, and many local districts | Manhasset–Lakeville, Jericho, Hicksville, Garden City Park |
Understanding who supplies your water helps you know where to go for billing questions, annual water quality reports, conservation programs, service alerts, and emergency notices. Since all of Long Island’s drinking water comes from aquifers, protecting groundwater from pollution and overuse is both a local and regional responsibility.
If you are moving, buying property, or comparing communities, it is always worth checking which authority or district serves the address. Service details, office hours, and reporting practices can vary by provider and may change over time.
