Nassau County tap water
11 of 33 water systems serving Nassau County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 40 community water systems list this county as served; 33 serve 3,300+ people with full PFAS testing.
- 3 had a health-based violation since 2021-10-26.
Largest systems serving this county
| System | Source | People served (whole system) | PFAS above a 2024 level? | Violations since 2021-10-26 |
|---|---|---|---|---|
| Liberty Utilities New York - Lynbrook | Groundwater | 220,000 | No | 5 |
| Liberty Utilities New York - Merrick | Groundwater | 135,000 | No | 3 |
| WA of Western Nassau | Groundwater | 120,000 | Yes | 0 |
| Town of Hempstead Water department | Groundwater | 110,000 | No | 0 |
| Jericho Wd | Groundwater | 58,000 | No | 1 |
| Hempstead (V) | Groundwater | 56,000 | No | 0 |
| Hicksville Wd | Groundwater | 48,000 | No | 0 |
| Freeport (V) | Groundwater | 45,000 | No | 0 |
| South Farmingdale Wd | Groundwater | 44,700 | No | 0 |
| Manhasset Lakeville Wd | Groundwater | 43,000 | Yes | 0 |
| Massapequa Wd | Groundwater | 43,000 | No | 0 |
| Long Beach City | Groundwater | 35,000 | No | 0 |
Which one is yours? A county usually has several utilities. Your bill or your utility's annual water-quality report names yours. Population is for the whole system, which can cross county lines.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.