Nassau County, New York
Violation Analysis
Water Source Types
PFAS Contamination
PFAS (per- and polyfluoroalkyl substances) are persistent chemicals found in drinking water. The EPA has set enforceable limits for several PFAS compounds under UCMR5 monitoring.
Compliance Snapshot
Nassau New York water systems by violation status, EPA SDWIS records.
Violation history is cumulative, many flagged systems have already returned to compliance. Detail pages show per-system context.
Water Systems
| System Name | Population | Violations | PFAS |
|---|---|---|---|
| Liberty Utilities New York - Lynbrook | 220,000 | 19 | Detected |
| Liberty Utilities New York - Merrick | 135,000 | 249 | Clean |
| WA of Western Nassau | 120,000 | 25 | Detected |
| Town of Hempstead Water Department | 110,000 | 2 | Detected |
| Jericho WD | 58,000 | 373 | Detected |
| Hempstead (V) | 56,000 | 237 | Detected |
| Hicksville WD | 48,000 | 9 | Detected |
| Freeport (V) | 45,000 | 5 | Clean |
| South Farmingdale WD | 44,700 | 1 | Clean |
| Manhasset Lakeville WD | 43,000 | 1,476 | Detected |
| Massapequa WD | 43,000 | 346 | Clean |
| Long Beach City | 35,000 | 21 | Clean |
| Plainview WD | 34,000 | 236 | Detected |
| Port Washington WD | 34,000 | 582 | Detected |
| Bethpage WD | 33,000 | 9 | Detected |
| West Hempstead WD | 32,031 | 327 | Clean |
| Jones Beach State Park | 30,799 | 17 | - |
| Glen Cove City | 28,000 | 534 | Detected |
| Rockville Centre (V) | 24,700 | 131 | Clean |
| Garden City (V) | 23,272 | 96 | Detected |
| Mineola (V) | 20,600 | 82 | Detected |
| Westbury WD | 20,500 | 34 | Detected |
| Franklin Square WD | 20,000 | 127 | Clean |
| Garden City Park WD | 18,000 | 16 | Detected |
| Roslyn WD | 17,000 | 95 | Detected |
| Albertson WD | 13,500 | 1,243 | Detected |
| Liberty Utilities New York - Sea Cliff | 13,400 | 9 | Clean |
| Carle Place WD | 9,005 | 248 | Clean |
| Farmingdale (V) | 8,744 | 8 | Clean |
| Oyster Bay WD | 8,700 | 12 | Detected |
| Locust Valley WD | 7,500 | 6 | Detected |
| Williston Park (V) | 7,287 | 14 | Detected |
| Bayville (V) | 6,700 | 76 | Clean |
| Old Westbury (V) | 4,700 | 9 | Clean |
| Sands Point (V) | 2,900 | 0 | - |
| East Williston (V) | 2,556 | 9 | - |
| Tobay Beach | 2,420 | 247 | - |
| Lido-Point Lookout WD | 2,000 | 16 | - |
| Plandome (V) | 1,600 | 20 | - |
| Cathedral Gardens WD | 1,500 | 76 | - |
| Glenwood WD | 1,000 | 1 | - |
| Liberty Utilities New York - Mill Neck | 280 | 18 | - |
| Seawanhaka Yacht Club | 60 | 298 | - |
| Beaver Dam Winter Sports | 35 | 112 | - |
Other Counties in New York
Drinking Water Guides
Frequently Asked Questions
How many water violations are in Nassau County? ▼
How many people get water from Nassau County systems? ▼
Has PFAS been detected in Nassau County water? ▼
What types of water sources supply Nassau County? ▼
Are health-based violations serious? ▼
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Violations are categorized as health-based (Maximum Contaminant Level exceedances, treatment technique failures) or monitoring/reporting violations. Not all violations indicate an immediate health risk.
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.