Washington County Water Quality: 2 Cities Ranked by the Records
Washington County, Rhode Island: 2 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.
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.
Perfluorooctanoic acid (PFOA)Detected in 2 systems4.0 ng/L federal MCL (2024) · US EPAHighest9 ng/L
- WESTERLY WATER DEPARTMENT9 ng/LSample date: 2025-05-14 to 2025-09-02
- NORTH KINGSTOWN TOWN OF8.1 ng/LSample date: 2023-09-20 to 2024-07-17
Perfluorooctanesulfonic acid (PFOS)Detected in 2 systems4.0 ng/L federal MCL (2024) · US EPAHighest7 ng/L
- WESTERLY WATER DEPARTMENT7 ng/LSample date: 2025-05-14 to 2025-09-02
- NORTH KINGSTOWN TOWN OF4.6 ng/LSample date: 2023-09-20 to 2024-07-17
Perfluorohexanesulfonic acid (PFHxS)Detected in 1 system of 2 tested10 ng/L federal MCL (2024) · US EPAHighest3.2 ng/L
- NORTH KINGSTOWN TOWN OF3.2 ng/LSample date: 2023-09-20 to 2024-07-17
- WESTERLY WATER DEPARTMENTNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-05-14 to 2025-09-02
Lead (90th percentile)Detected in 2 systems15 µg/L federal action level · US EPAHighest3.6 µg/L
- WESTERLY WATER DEPARTMENT3.6 µg/LMonitoring period: 2026–2026 (still open)
- NORTH KINGSTOWN TOWN OF1.3 µg/LMonitoring period: 2023–2025
Perfluorobutanesulfonic acid (PFBS)Detected in 2 systems2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPAHighest7.7 ng/L
- NORTH KINGSTOWN TOWN OF7.7 ng/LSample date: 2023-09-20 to 2024-07-17
- WESTERLY WATER DEPARTMENT3 ng/LSample date: 2025-05-14 to 2025-09-02
Perfluorohexanoic acid (PFHxA)Detected in 2 systems400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest6.3 ng/L
- NORTH KINGSTOWN TOWN OF6.3 ng/LSample date: 2023-09-20 to 2024-07-17
- WESTERLY WATER DEPARTMENT5 ng/LSample date: 2025-05-14 to 2025-09-02
Perfluorobutanoic acid (PFBA)Detected in 1 system of 2 testedNo federal or state limit; shown for transparencyHighest10 ng/L
- WESTERLY WATER DEPARTMENT10 ng/LSample date: 2025-05-14 to 2025-09-02
- NORTH KINGSTOWN TOWN OFNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-07-17
Perfluoroheptanoic acid (PFHpA)Detected in 1 system of 2 testedNo federal or state limit; shown for transparencyHighest3 ng/L
- WESTERLY WATER DEPARTMENT3 ng/LSample date: 2025-05-14 to 2025-09-02
- NORTH KINGSTOWN TOWN OFNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-20 to 2024-07-17
1 more contaminant detectedShow
Perfluoropentanoic acid (PFPeA)Detected in 2 systemsNo federal or state limit; shown for transparencyHighest6.1 ng/L
- NORTH KINGSTOWN TOWN OF6.1 ng/LSample date: 2023-09-20 to 2024-07-17
- WESTERLY WATER DEPARTMENT6 ng/LSample date: 2025-05-14 to 2025-09-02
22 substances tested, none detected in any systemShow
Tested in these 2 systems: NORTH KINGSTOWN TOWN OF, WESTERLY WATER DEPARTMENT
- 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)
- 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 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)
- Lithium
- 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)
- Perfluorononanoic acid (PFNA)
- Perfluoropentanesulfonic acid (PFPeS)
- Perfluorotetradecanoic acid (PFTA)
- Perfluorotridecanoic acid (PFTrDA)
- Perfluoroundecanoic acid (PFUnA)
Cities ranked by the records
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.
0of 2 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 Rhode IslandLargest water systems
- WesterlyWESTERLY WATER DEPARTMENT · RI155951235,298 served
- North KingstownNORTH KINGSTOWN TOWN OF · RI155951727,732 served
Frequently asked
How does Washington County tap water compare across cities?
PurityMap ranks 2 cities in Washington 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 North Kingstown's main water system: NORTH KINGSTOWN TOWN OF · PWSID RI1559517 · Purity Score 56 (Fair) · 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 Washington County cities had a PFAS sample above a 2024 EPA limit?
2 of 2 Washington County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Westerly (PFOA 9 ng/L), North Kingstown (PFOA 8.1 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 2.
Is there lead in Washington County tap water?
Utilities report lead as a 90th-percentile result from home taps. 2 of 2 Washington 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.
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