Suffolk County tap water
1 of 10 water systems serving Suffolk County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 26 community water systems list this county as served; 10 serve 3,300+ people with full PFAS testing.
- 1 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 |
|---|---|---|---|---|
| Suffolk County Water Authority | Groundwater | 1,100,000 | Yes | 0 |
| South Huntington Water District | Groundwater | 81,760 | No | 0 |
| Greenlawn Water District | Groundwater | 42,000 | No | 0 |
| Riverhead Water District | Groundwater | 35,000 | No | 1 |
| Dix Hills Water District | Groundwater | 34,522 | No | 0 |
| Smithtown Water District | Purchased groundwater | 19,635 | No | 0 |
| Hampton Bays Water District | Groundwater | 12,500 | No | 0 |
| St James Water District | Purchased groundwater | 10,587 | No | 0 |
| Ocean Beach Water District | Groundwater | 4,500 | No | 0 |
| Brookhaven National Laboratory | Groundwater | 3,500 | 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.