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Updated 2026-10-15
County water report

Nassau County Water Quality: 17 Cities Ranked by the Records

Nassau County, New York: 17 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my systemOpen on the mapPrivate wells in Nassau County
Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

LithiumDetected in 4 systems of 17 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest139 µg/L
  • LIBERTY UTILITIES NEW YORK - MERRICK139 µg/LSample date: 2023-03-28 to 2025-06-26
  • LONG BEACH CITY28.4 µg/LSample date: 2024-03-14 to 2024-09-19
  • WOODBURY CONS. W.D.21.3 µg/LSample date: 2023-08-28 to 2024-04-03
  • LIBERTY UTILITIES NEW YORK - LYNBROOK14.9 µg/LSample date: 2023-04-11 to 2025-07-15
  • BETHPAGE WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-01-10 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-10-30 to 2024-04-08
  • HICKSVILLE WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-06-26 to 2025-12-29
  • JERICHO WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-04-25 to 2025-11-12
  • MASSAPEQUA WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • PORT WASHINGTON WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-02-14 to 2026-01-12
  • SOUTH FARMINGDALE WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WA OF WESTERN NASSAUNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-06-13 to 2023-12-07
  • WESTBURY WDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
Perfluorooctanoic acid (PFOA)Detected in 4 systems of 17 tested4.0 ng/L federal MCL (2024) · US EPAHighest10 ng/L
  • WA OF WESTERN NASSAU10 ng/LSample date: 2023-06-13 to 2024-01-25
  • WESTBURY WD7.6 ng/LSample date: 2024-01-09 to 2025-12-09
  • PORT WASHINGTON WD5.3 ng/LSample date: 2023-02-14 to 2026-06-09
  • GLEN COVE CITY4.5 ng/LSample date: 2023-10-30 to 2024-05-06
  • BETHPAGE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • HICKSVILLE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • JERICHO WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-28 to 2025-11-12
  • LIBERTY UTILITIES NEW YORK - LYNBROOKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-11 to 2025-07-15
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • SOUTH FARMINGDALE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WOODBURY CONS. W.D.Not detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluorooctanesulfonic acid (PFOS)Detected in 3 systems of 17 tested4.0 ng/L federal MCL (2024) · US EPAHighest6.1 ng/L
  • WA OF WESTERN NASSAU6.1 ng/LSample date: 2023-06-13 to 2024-01-25
  • LIBERTY UTILITIES NEW YORK - LYNBROOK5.1 ng/LSample date: 2023-04-11 to 2025-07-15
  • PORT WASHINGTON WD4.7 ng/LSample date: 2023-02-14 to 2026-06-09
  • BETHPAGE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • JERICHO WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-28 to 2025-11-12
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • SOUTH FARMINGDALE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WESTBURY WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluorohexanesulfonic acid (PFHxS)Detected in 2 systems of 17 tested10 ng/L federal MCL (2024) · US EPAHighest6.3 ng/L
  • LIBERTY UTILITIES NEW YORK - LYNBROOK6.3 ng/LSample date: 2023-04-11 to 2025-07-15
  • WA OF WESTERN NASSAU4.5 ng/LSample date: 2023-06-13 to 2024-01-25
  • BETHPAGE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • JERICHO WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-28 to 2025-11-12
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • PORT WASHINGTON WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-14 to 2026-06-09
  • SOUTH FARMINGDALE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WESTBURY WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Lead (90th percentile)Detected in 11 systems of 17 tested15 µg/L federal action level · US EPAHighest8.5 µg/L
Perfluorononanoic acid (PFNA)Detected in 2 systems of 17 tested10 ng/L federal MCL (2024) · US EPAHighest4.2 ng/L
  • PORT WASHINGTON WD4.2 ng/LSample date: 2023-02-14 to 2026-06-09
  • LIBERTY UTILITIES NEW YORK - LYNBROOK4.1 ng/LSample date: 2023-04-11 to 2025-07-15
  • BETHPAGE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • JERICHO WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-28 to 2025-11-12
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • SOUTH FARMINGDALE WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WA OF WESTERN NASSAUNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-13 to 2024-01-25
  • WESTBURY WDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluorobutanesulfonic acid (PFBS)Detected in 2 systems of 17 tested2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest3.6 ng/L
  • WA OF WESTERN NASSAU3.6 ng/LSample date: 2023-06-13 to 2024-01-25
  • BETHPAGE WD3.5 ng/LSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • JERICHO WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-28 to 2025-11-12
  • LIBERTY UTILITIES NEW YORK - LYNBROOKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-11 to 2025-07-15
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • PORT WASHINGTON WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-14 to 2026-06-09
  • SOUTH FARMINGDALE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WESTBURY WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluorohexanoic acid (PFHxA)Detected in 5 systems of 17 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest18 ng/L
4 more contaminants detectedShow
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)Detected in 2 systems of 17 testedNo federal or state limit; shown for transparencyHighest9.9 ng/L
  • JERICHO WD9.9 ng/LSample date: 2023-04-28 to 2025-11-12
  • PORT WASHINGTON WD6.5 ng/LSample date: 2023-02-14 to 2026-06-09
  • BETHPAGE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • LIBERTY UTILITIES NEW YORK - LYNBROOKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-11 to 2025-07-15
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • SOUTH FARMINGDALE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WA OF WESTERN NASSAUNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-13 to 2024-01-25
  • WESTBURY WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluorobutanoic acid (PFBA)Detected in 4 systems of 17 testedNo federal or state limit; shown for transparencyHighest67 ng/L
  • JERICHO WD67 ng/LSample date: 2023-04-28 to 2025-11-12
  • PLAINVIEW WD10.9 ng/LSample date: 2024-05-01 to 2024-11-14
  • BETHPAGE WD9.3 ng/LSample date: 2023-02-22 to 2023-07-25
  • WA OF WESTERN NASSAU7.1 ng/LSample date: 2023-06-13 to 2024-01-25
  • FRANKLIN SQUARE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • LIBERTY UTILITIES NEW YORK - LYNBROOKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-11 to 2025-07-15
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PORT WASHINGTON WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-02-14 to 2026-06-09
  • SOUTH FARMINGDALE WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WESTBURY WDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluoroheptanoic acid (PFHpA)Detected in 2 systems of 17 testedNo federal or state limit; shown for transparencyHighest4.6 ng/L
  • JERICHO WD4.6 ng/LSample date: 2023-04-28 to 2025-11-12
  • WA OF WESTERN NASSAU3.4 ng/LSample date: 2023-06-13 to 2024-01-25
  • BETHPAGE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-22 to 2023-07-25
  • FRANKLIN SQUARE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-02 to 2024-10-08
  • GLEN COVE CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-30 to 2024-05-06
  • HICKSVILLE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-26 to 2026-06-17
  • LIBERTY UTILITIES NEW YORK - LYNBROOKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-11 to 2025-07-15
  • LIBERTY UTILITIES NEW YORK - MERRICKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-11-22
  • LONG BEACH CITYNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-14 to 2024-09-19
  • MASSAPEQUA WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-27 to 2025-07-15
  • PLAINVIEW WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-01 to 2024-11-14
  • PORT WASHINGTON WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-14 to 2026-06-09
  • SOUTH FARMINGDALE WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-15 to 2024-07-30
  • TOWN OF HEMPSTEAD WATER DEPARTMENTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-13 to 2024-12-18
  • WA OF GREAT NECK NORTHNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-09-18
  • WESTBURY WDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-09 to 2025-12-09
  • WOODBURY CONS. W.D.Not detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-28 to 2024-04-03
Perfluoropentanoic acid (PFPeA)Detected in 9 systems of 17 testedNo federal or state limit; shown for transparencyHighest37 ng/L
19 PFAS tested, none detected in any systemShow

Tested in these 17 systems: BETHPAGE WD, FRANKLIN SQUARE WD, GLEN COVE CITY, HICKSVILLE WD, JERICHO WD, LIBERTY UTILITIES NEW YORK - LYNBROOK, LIBERTY UTILITIES NEW YORK - MERRICK, LONG BEACH CITY, MASSAPEQUA WD, PLAINVIEW WD, PORT WASHINGTON WD, SOUTH FARMINGDALE WD, TOWN OF HEMPSTEAD WATER DEPARTMENT, WA OF GREAT NECK NORTH, WA OF WESTERN NASSAU, WESTBURY WD, WOODBURY CONS. W.D.

  • 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
  • 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
  • 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
  • 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
  • N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
  • N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
  • Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
  • Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
  • Perfluoro-3-methoxypropanoic acid (PFMPA)
  • Perfluoro-4-methoxybutanoic acid (PFMBA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluoroheptanesulfonic acid (PFHpS)
  • Perfluoropentanesulfonic acid (PFPeS)
  • Perfluorotetradecanoic acid (PFTA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
17 cities

Cities ranked by the records

Showing 6 of 17 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Nassau County5 of 17 city reports had a PFAS sample above a 2024 EPA limit
  1. Elmont6.1 ng/L
  2. Valley Stream5.1 ng/L
  3. Port Washington4.7 ng/L
4.0 ng/L federal MCL · PFOS, ng/LPFAS in New York
Lead

0of 17 cities above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in New York
Who supplies the county

Largest water systems

  1. Valley StreamLIBERTY UTILITIES NEW YORK - LYNBROOK · NY2902835
    220,000 served
  2. MerrickLIBERTY UTILITIES NEW YORK - MERRICK · NY2902840
    135,000 served
  3. ElmontWA OF WESTERN NASSAU · NY2902830
    120,000 served
  4. HempsteadTOWN OF HEMPSTEAD WATER DEPARTMENT · NY2900000
    110,000 served
  5. SyossetJERICHO WD · NY2902831
    58,000 served
  6. HicksvilleHICKSVILLE WD · NY2902829
    48,000 served
  7. North MassapequaSOUTH FARMINGDALE WD · NY2902854
    44,700 served
  8. MassapequaMASSAPEQUA WD · NY2902837
    43,000 served
  9. Long BeachLONG BEACH CITY · NY2902834
    35,000 served
  10. PlainviewPLAINVIEW WD · NY2902845
    34,000 served
Questions

Frequently asked

How does Nassau County tap water compare across cities?

PurityMap ranks 17 cities in Nassau County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Massapequa's main water system: MASSAPEQUA WD · PWSID NY2902837 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Nassau County cities had a PFAS sample above a 2024 EPA limit?

5 of 17 Nassau County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Elmont (PFOA 10 ng/L), Westbury (PFOA 7.6 ng/L), Port Washington (PFOA 5.3 ng/L). That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. PFAS were detected at any level in 11.

Is there lead in Nassau County tap water?

Utilities report lead as a 90th-percentile result from home taps. 11 of 17 Nassau County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

Have Nassau County water systems had drinking-water violations?

2 cities in Nassau County have a health-based violation in the federal SDWIS record within about the last ten years. Each city report lists the contaminant, year and whether it was resolved.

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