- PWSID
- MD0060003
- State
- Maryland
- System type
- community water system (CWS)
- Population served
- 6,600
- City
- Hampstead
- Counties
- Carroll County
- Primary source water
- groundwater
- UCMR 5 sampling
- 2023-02-07 to 2023-08-16 · 10 entry point(s) · water types: GW
- Service-area boundary
- authoritative
PFOA 1–3 × its limit highest single result
PFOA 1–3 × its limit worst entry-point average
Open on the Maryland map · All Maryland 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) | 9.1 | 9.05 | 4 |
| PFOS (ppt) | 5.7 | 5.45 | 4 |
| Hazard Index | 0.343 | 0.173 | 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).
No Maryland PFAS drinking-water standard in effect or proposed as of 2026-10-17: No Maryland-specific PFAS drinking-water MCL; MDE implementing federal NPDWR.
Sampling history
Sampled 2023-02-07 to 2023-08-16 · 10 entry point(s) · water types: GW · 20 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | 6.7 | 5.2 | 0.002 | PFHpA 3.2, PFHxA 5.3, PFPeA 5.2 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | 4 | <4 | 0.004 | PFHxA 4.8, PFPeA 5 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | 9.1 | <4 | 0.003 | PFBA 5.6, PFHpA 5.2, PFHxA 14.9, PFPeA 17.3 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0.002 | PFHxA 3.4, PFPeA 3.7 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0.005 | PFHxA 5.6, PFPeA 4.9 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0.006 | PFHxA 5.5, PFPeA 6.7 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | 6.6 | 4 | 0.004 | PFHpA 3.6, PFHxA 5, PFPeA 5.2 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0.003 | none |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0.002 | PFHxA 3.2, PFPeA 3.1 |
| 2023-02-07 | TOWN OF HAMPSTEAD (GW) | SE1 | <4 | <4 | 0 | PFHxA 3 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 7.8 | 5.7 | 0.343 | PFHpA 3.5, PFHxA 5.9, PFPeA 5.9 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 5.3 | <4 | 0.005 | PFHpA 3, PFHxA 5.6, PFPeA 6.1 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 9 | <4 | 0.003 | PFBA 5.3, PFHpA 5.1, PFHxA 13.4, PFPeA 15.6 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | <4 | <4 | 0.002 | PFHxA 4.5, PFPeA 4.9 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | <4 | <4 | 0.005 | PFHxA 5.6, PFPeA 5.4 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | <4 | <4 | 0.007 | PFPeA 6.5 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 7.9 | <4 | 0.004 | PFBA 5.3, PFHpA 4.1, PFHxA 5.8, PFPeA 5.7 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | <4 | <4 | 0.003 | none |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 4.7 | <4 | 0.003 | PFHxA 4.2, PFPeA 4.1 |
| 2023-08-16 | TOWN OF HAMPSTEAD (GW) | SE2 | 4.9 | <4 | 0.002 | PFHxA 3.3, PFPeA 3.2 |
“<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
600 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.
TOWN OF HAMPSTEAD facility TP02 · sample point EP02 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 4.9 | 6.3 |
| PFHpA | 3 ppt | 3.2 | 3.5 |
| PFHxA | 3 ppt | 5.3 | 5.9 |
| PFHxS | 3 ppt | < 3 | 3.4 |
| PFOA | 4 ppt | 6.7 | 7.8 |
| PFOS | 4 ppt | 5.2 | 5.7 |
| PFPeA | 3 ppt | 5.2 | 5.9 |
| 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 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| 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 |
TOWN OF HAMPSTEAD facility TP03 · sample point EP03 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 7 | 9.1 |
| PFHpA | 3 ppt | < 3 | 3 |
| PFHxA | 3 ppt | 4.8 | 5.6 |
| PFOA | 4 ppt | 4 | 5.3 |
| PFPeA | 3 ppt | 5 | 6.1 |
| 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 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| 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 |
TOWN OF HAMPSTEAD facility TP05 · sample point EP05 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5.6 | 5.3 |
| PFBS | 3 ppt | 5.3 | 5.3 |
| PFHpA | 3 ppt | 5.2 | 5.1 |
| PFHxA | 3 ppt | 14.9 | 13.4 |
| PFOA | 4 ppt | 9.1 | 9 |
| PFPeA | 3 ppt | 17.3 | 15.6 |
| 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 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| 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 |
TOWN OF HAMPSTEAD facility TP07 · sample point EP07 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 3.7 | 4.3 |
| PFHxA | 3 ppt | 3.4 | 4.5 |
| PFPeA | 3 ppt | 3.7 | 4.9 |
| 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 |
| 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 |
| 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 |
| 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 |
TOWN OF HAMPSTEAD facility TP09 · sample point EP09 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 9.1 | 10.5 |
| PFHxA | 3 ppt | 5.6 | 5.6 |
| PFPeA | 3 ppt | 4.9 | 5.4 |
| 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 |
| 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 |
| 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 |
| 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 |
TOWN OF HAMPSTEAD facility TP10 · sample point EP10 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 11.1 | 13.4 |
| PFHxA | 3 ppt | 5.5 | < 3 |
| PFPeA | 3 ppt | 6.7 | 6.5 |
| 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 |
| 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 |
| 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 |
| 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 |
TOWN OF HAMPSTEAD facility TP11 · sample point EP11 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 5.3 |
| PFBS | 3 ppt | 7.1 | 8.3 |
| PFHpA | 3 ppt | 3.6 | 4.1 |
| PFHxA | 3 ppt | 5 | 5.8 |
| PFOA | 4 ppt | 6.6 | 7.9 |
| PFOS | 4 ppt | 4 | < 4 |
| PFPeA | 3 ppt | 5.2 | 5.7 |
| 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 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| 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 |
TOWN OF HAMPSTEAD facility TP12 · sample point EP12 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 5.9 | 6.1 |
| 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 |
| 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 |
TOWN OF HAMPSTEAD facility TP13 · sample point EP13 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 3.8 | 5.6 |
| PFHxA | 3 ppt | 3.2 | 4.2 |
| PFOA | 4 ppt | < 4 | 4.7 |
| PFPeA | 3 ppt | 3.1 | 4.1 |
| 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 |
| 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 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| 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 |
TOWN OF HAMPSTEAD facility TP14 · sample point EP14 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-16 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | < 3 | 3.3 |
| PFHxA | 3 ppt | 3 | 3.3 |
| PFOA | 4 ppt | < 4 | 4.9 |
| PFPeA | 3 ppt | < 3 | 3.2 |
| 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 |
| 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 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| 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 |
|---|---|---|---|---|---|---|---|---|
| PFBS | 20 | 95% | 13.4 2023-08-16 | 6.5–6.66 | 5.9 | 8.3 | 10.5 | 11.1 |
| PFHxA | 20 | 85% | 14.9 2023-02-07 | 4.95–5.4 | 4.8 | 5.6 | 5.9 | 13.4 |
| PFPeA | 20 | 85% | 17.3 2023-02-07 | 5.42–5.88 | 5 | 5.9 | 6.7 | 15.6 |
| PFOA | 20 | 50% | 9.1 2023-02-07 | 3.3–5.3 | <MRL | 6.6 | 7.9 | 9 |
| PFHpA | 20 | 35% | 5.2 2023-02-07 | 1.39–3.33 | <MRL | 3.2 | 4.1 | 5.1 |
| PFBA | 20 | 15% | 5.6 2023-02-07 | 0.81–5.06 | <MRL | <MRL | 5.3 | 5.3 |
| PFOS | 20 | 15% | 5.7 2023-08-16 | 0.74–4.14 | <MRL | <MRL | 4 | 5.2 |
| PFHxS | 20 | 5% | 3.4 2023-08-16 | 0.17–3.02 | <MRL | <MRL | <MRL | <MRL |
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 2023-01-04 to 2026-05-19; 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 a5d4ffe50da4 · 2026-10-18T04:05Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.