- PWSID
- MA4001000
- State
- Massachusetts
- System type
- community water system (CWS)
- Population served
- 33,387
- City
- Rockland
- Counties
- Plymouth County
- Primary source water
- surface water
- UCMR 5 sampling
- 2024-05-17 to 2025-02-06 · 3 entry point(s) · water types: GW;SW
- Service-area boundary
- authoritative
PFOA ≥ 3 × its limit highest single result
PFOA 1–3 × its limit worst entry-point average
Open on the Massachusetts map · All Massachusetts systems · All results
These are monitoring results collected under EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) at entry points, where treated water enters the distribution system; they are not tap-water samples. They are not compliance determinations: compliance with EPA's 2024 PFAS limits is judged on running annual averages of compliance monitoring, required from 2029, so a single UCMR 5 result at or above a limit is not a violation. “< MRL” means the compound was not quantified at EPA's minimum reporting level; it does not mean zero.
Compared with EPA's 2024 values
| Highest single result | Worst entry-point average* | Limit | |
|---|---|---|---|
| PFOA (ppt) | 12 | 11.5 | 4 |
| PFOS (ppt) | 7 | 7 | 4 |
| Hazard Index | 0.402 | 0.351 | 1.0† |
“<MRL” = every result for the compound was below its reporting limit. * Mean of all samples at each entry point with non-detects = 0 (EPA compliance convention; the Hazard Index also uses non-detects = 0); a screening comparison, not a formal running annual average. † Rescission proposed May 2026. PFOA/PFOS MCL 4 ppt (2024 NPDWR, in effect). PFHxS, PFNA, HFPO-DA (10 ppt each) and the Hazard Index (1.0) are 2024 NPDWR values; EPA proposed rescinding them on 18 May 2026 (comment period closed 20 Jul 2026).
Compared with Massachusetts standards
| Highest single result | Worst entry-point average* | Massachusetts | |
|---|---|---|---|
| PFAS6 (sum) (ppt) | 31 | 28.5 | 20 |
Sum standards add the listed compounds within each sample (non-detects = 0). State compliance is normally judged on averages over time; these are screening comparisons.
Sampling history
Sampled 2024-05-17 to 2025-02-06 · 3 entry point(s) · water types: GW;SW · 14 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2024-05-17 | Great Sandy Bottom Pond WTP (SW) | SE1 | <4 | <4 | 0 | none |
| 2024-05-17 | Hingham Street WTP (SW) | SE1 | n/a | n/a | n/a | none |
| 2024-05-17 | Myers Avenue WTP (GW) | SE1 | <4 | <4 | 0 | none |
| 2024-05-31 | Hingham Street WTP (SW) | SE1 | 11 | 7 | 0.301 | PFBA 10, PFHpA 5, PFHxA 11, PFPeA 19 |
| 2024-08-28 | Great Sandy Bottom Pond WTP (SW) | SE2 | n/a | n/a | n/a | none |
| 2024-08-28 | Hingham Street WTP (SW) | SE2 | n/a | n/a | n/a | none |
| 2024-10-18 | Great Sandy Bottom Pond WTP (SW) | SE2 | 5 | <4 | 0 | PFBA 7, PFHxA 3, PFPeA 3 |
| 2024-10-18 | Hingham Street WTP (SW) | SE2 | 11 | 7 | 0.301 | PFBA 25, PFHpA 6, PFHxA 12, PFPeA 20 |
| 2024-10-18 | Myers Avenue WTP (GW) | SE2 | <4 | <4 | 0 | none |
| 2024-12-13 | Great Sandy Bottom Pond WTP (SW) | SE3 | 4 | <4 | 0 | PFHxA 3, PFPeA 3 |
| 2024-12-13 | Hingham Street WTP (SW) | SE3 | n/a | n/a | n/a | none |
| 2025-01-23 | Hingham Street WTP (SW) | SE3 | 12 | 7 | 0.402 | PFBA 16, PFHpA 8, PFHxA 18, PFPeA 32 |
| 2025-02-06 | Great Sandy Bottom Pond WTP (SW) | SE4 | 4 | <4 | 0 | PFBA 6, PFHxA 3, PFPeA 3 |
| 2025-02-06 | Hingham Street WTP (SW) | SE4 | 12 | 7 | 0.402 | PFBA 18, PFHpA 7, PFHxA 17, PFPeA 30 |
“<4” = not detected at the reporting limit shown; “n/a” = not analyzed in that sample. Highlighted = at or above the 4 ppt MCL. HI computed per sample with non-detects as 0. Other detections lists every other quantified compound (lithium in µg/L).
All results by entry point
300 results. Each column is one sampling visit (date and UCMR 5 sample event). A number is a measured concentration; “< 4” = below the minimum reporting level shown; “–” = not analyzed in that visit. PFAS in ppt (ng/L); lithium in µg/L.
Great Sandy Bottom Pond WTP facility 10344 · sample point 1593 · surface water
| Compound | MRL | 2024-05-17 SE1 | 2024-08-28 SE2 | 2024-10-18 SE2 | 2024-12-13 SE3 | 2025-02-06 SE4 |
|---|---|---|---|---|---|---|
| PFBA | 5 ppt | < 5 | – | 7 | < 5 | 6 |
| PFHxA | 3 ppt | < 3 | – | 3 | 3 | 3 |
| PFOA | 4 ppt | < 4 | – | 5 | 4 | 4 |
| PFPeA | 3 ppt | < 3 | – | 3 | 3 | 3 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | – | < 5 | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | – | < 5 | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | – | < 5 | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | – | < 2 | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | – | < 5 | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 | – | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | – | < 20 | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 | – | < 6 | < 6 |
| PFBS | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFDA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | – | < 3 | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | – | < 4 | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | – | < 4 | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | – | < 4 | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | – | < 4 | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 | – | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 | – | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | – | < 2 | < 2 | < 2 |
| lithium | 9 µg/L | < 9 | < 9 | – | < 9 | < 9 |
Hingham Street WTP facility 10345 · sample point 1594 · surface water
| Compound | MRL | 2024-05-17 SE1 | 2024-05-31 SE1 | 2024-08-28 SE2 | 2024-10-18 SE2 | 2024-12-13 SE3 | 2025-01-23 SE3 | 2025-02-06 SE4 |
|---|---|---|---|---|---|---|---|---|
| PFBA | 5 ppt | – | 10 | – | 25 | – | 16 | 18 |
| PFBS | 3 ppt | – | 3 | – | 3 | – | 3 | 3 |
| PFHpA | 3 ppt | – | 5 | – | 6 | – | 8 | 7 |
| PFHxA | 3 ppt | – | 11 | – | 12 | – | 18 | 17 |
| PFHxS | 3 ppt | – | 3 | – | 3 | – | 4 | 4 |
| PFOA | 4 ppt | – | 11 | – | 11 | – | 12 | 12 |
| PFOS | 4 ppt | – | 7 | – | 7 | – | 7 | 7 |
| PFPeA | 3 ppt | – | 19 | – | 20 | – | 32 | 30 |
| 11Cl-PF3OUdS | 5 ppt | – | < 5 | – | < 5 | – | < 5 | < 5 |
| 4:2 FTS | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| 6:2 FTS | 5 ppt | – | < 5 | – | < 5 | – | < 5 | < 5 |
| 8:2 FTS | 5 ppt | – | < 5 | – | < 5 | – | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | – | < 2 | – | < 2 | – | < 2 | < 2 |
| ADONA | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| HFPO-DA | 5 ppt | – | < 5 | – | < 5 | – | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | – | < 5 | – | < 5 | – | < 5 |
| NFDHA | 20 ppt | – | < 20 | – | < 20 | – | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | – | < 6 | – | < 6 | – | < 6 |
| PFDA | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| PFDoA | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| PFEESA | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| PFHpS | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| PFMBA | 3 ppt | – | < 3 | – | < 3 | – | < 3 | < 3 |
| PFMPA | 4 ppt | – | < 4 | – | < 4 | – | < 4 | < 4 |
| PFNA | 4 ppt | – | < 4 | – | < 4 | – | < 4 | < 4 |
| PFPeS | 4 ppt | – | < 4 | – | < 4 | – | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | – | < 8 | – | < 8 | – | < 8 |
| PFTrDA | 7 ppt | < 7 | – | < 7 | – | < 7 | – | < 7 |
| PFUnA | 2 ppt | – | < 2 | – | < 2 | – | < 2 | < 2 |
| lithium | 9 µg/L | < 9 | – | < 9 | – | < 9 | – | < 9 |
Myers Avenue WTP facility 10005 · sample point 19400 · groundwater
| Compound | MRL | 2024-05-17 SE1 | 2024-10-18 SE2 |
|---|---|---|---|
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFBA | 5 ppt | < 5 | < 5 |
| PFBS | 3 ppt | < 3 | < 3 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxA | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeA | 3 ppt | < 3 | < 3 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | < 9 | < 9 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| PFHxA | 10 | 70% | 18 2025-01-23 | 6.7–7.6 | 3 | 12 | 17 | 18 |
| PFOA | 10 | 70% | 12 2025-01-23 | 5.9–7.1 | 4 | 11 | 12 | 12 |
| PFPeA | 10 | 70% | 32 2025-01-23 | 11–11.9 | 3 | 20 | 30 | 32 |
| PFBA | 10 | 60% | 25 2024-10-18 | 8.2–10.2 | 6 | 16 | 18 | 25 |
| PFBS | 10 | 40% | 3 2024-05-31 | 1.2–3 | <MRL | 3 | 3 | 3 |
| PFHpA | 10 | 40% | 8 2025-01-23 | 2.6–4.4 | <MRL | 6 | 7 | 8 |
| PFHxS | 10 | 40% | 4 2025-01-23 | 1.4–3.2 | <MRL | 3 | 4 | 4 |
| PFOS | 10 | 40% | 7 2024-05-31 | 2.8–5.2 | <MRL | 7 | 7 | 7 |
Never detected (22): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFDA, PFDoA, PFEESA, PFHpS, PFMBA, PFMPA, PFNA, PFPeS, PFTA, PFTrDA, PFUnA, lithium.
Left-censored Kaplan–Meier statistics (Helsel 2005; Helsel & Lee 2006, NADA for R). Units: ppt; lithium µg/L. Each compound has one reporting limit, so the Kaplan–Meier mean equals the upper mean bound (non-detects at the MRL); the lower bound sets non-detects to 0. “<MRL” = the percentile falls below the reporting limit and cannot be estimated. These describe this system's UCMR 5 samples, not population estimates.
Sources
- EPA UCMR 5 occurrence data text files (UCMR5_All.txt; samples 2023-01-09 to 2026-05-28; data summary dated Jul 2026)
- EPA SDWIS via ECHO SDWA downloads, quarter 2026Q3
- EPA Public Water System Service Areas v3 (Mar 2026)
- US Census Bureau cartographic boundary counties 1:500k, 2024
- EPA/USGS NHDPlus V2 (medium resolution) flowlines, Strahler order 2+
Data build a6eeb89a233e · 2026-10-18T04:09Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.