- PWSID
- PA1460020
- State
- Pennsylvania
- System type
- community water system (CWS)
- Population served
- 20,000
- City
- Ambler
- Counties
- Montgomery County
- Primary source water
- surface water
- UCMR 5 sampling
- 2024-08-19 to 2025-05-13 · 9 entry point(s) · water types: GW;SW
- Service-area boundary
- authoritative
PFOA ≥ 3 × its limit highest single result
PFOA ≥ 3 × its limit worst entry-point average
Open on the Pennsylvania map · All Pennsylvania 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.
Water purchased from
- North Wales Water Authority (PA1460048)
Seller's highest results: PFOA 13 ppt · PFOS 11.1 ppt · HI 0.563 · detected: PFBA;PFBS;PFHpA;PFHxA;PFHxS;PFNA;PFOA;PFOS;PFPeA - Aqua Pa Main System (PA1460073)
Seller's highest results: PFOA 12.6 ppt · PFOS 9.2 ppt · HI 1.203 · detected: PFBA;PFBS;PFHpA;PFHxA;PFHxS;PFNA;PFOA;PFOS;PFPeA
Seller results are the seller's own entry-point samples, not measurements of this system's water. This system's own samples (below) may reflect purchased water, its own sources, or both.
Compared with EPA's 2024 values
| Highest single result | Worst entry-point average* | Limit | |
|---|---|---|---|
| PFOA (ppt) | 15.3 | 14.1 | 4 |
| PFOS (ppt) | 13.7 | 12.55 | 4 |
| Hazard Index | 1.793 | 1.594 | 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 Pennsylvania standards
| Highest single result | Worst entry-point average* | Pennsylvania | |
|---|---|---|---|
| PFOA (ppt) | 15.3 | 14.1 | 14 |
| PFOS (ppt) | 13.7 | 12.55 | 18 |
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 2024-08-19 to 2025-05-13 · 9 entry point(s) · water types: GW;SW · 38 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2024-08-19 | Loch Alsh Well #2 Treatment (GW) | SE1 | 14.2 | 12.4 | 1.793 | 6:2 FTS 6, PFBA 8, PFHpA 9, PFHxA 12.2, PFPeA 14, lithium 11.2 µg/L |
| 2024-08-19 | Loch Alsh Well #6 Treatment (GW) | SE1 | 10 | 13.5 | 0.413 | PFHpA 4.2, PFHxA 6, PFPeA 5.5, lithium 9.9 µg/L |
| 2024-08-19 | Loch Alsh Well #7 Treatment (GW) | SE1 | 10.5 | 10.6 | 0.505 | PFBA 5.7, PFHpA 4.5, PFHxA 5.8, PFPeA 5.6 |
| 2024-08-19 | Well #11 Treatment (GW) | SE1 | 10.4 | 8.6 | 0.444 | PFBA 6.7, PFHpA 4.6, PFHxA 7.9, PFPeA 7.7, lithium 12.4 µg/L |
| 2024-08-19 | Well #12 Treatment (GW) | SE1 | 8.7 | 8 | 0.003 | PFBA 5, PFHpA 4.1, PFHxA 7.5, PFPeA 6.6, lithium 12 µg/L |
| 2024-08-19 | Well #14 Treatment (GW) | SE1 | 9 | 9.5 | 0.004 | PFBA 5.9, PFHpA 4.2, PFHxA 9.5, PFPeA 6.8, lithium 11.6 µg/L |
| 2024-08-19 | Well #4 Treatment (GW) | SE1 | 10.2 | 9.8 | 0.373 | PFBA 6.4, PFHpA 4.2, PFHxA 6, PFPeA 6.7, lithium 12.9 µg/L |
| 2024-08-19 | Well #9 Treatment (GW) | SE1 | 12.9 | 13.7 | 0.454 | PFBA 6, PFHpA 5.2, PFHxA 7.6, PFPeA 6.9, lithium 21.9 µg/L |
| 2024-08-19 | Whitemarsh Spring Treatment (SW) | SE1 | <4 | <4 | 0 | PFBA 7.1 |
| 2024-09-09 | Loch Alsh Well #2 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Loch Alsh Well #6 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Loch Alsh Well #7 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Well #11 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Well #12 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Well #14 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Well #4 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Well #9 Treatment (GW) | SE1 | n/a | n/a | n/a | none |
| 2024-09-09 | Whitemarsh Spring Treatment (SW) | SE1 | n/a | n/a | n/a | none |
| 2024-11-06 | Whitemarsh Spring Treatment (SW) | SE2 | <4 | <4 | 0 | PFBA 10.6, PFHxA 4.5, PFPeA 10.4 |
| 2025-02-03 | Loch Alsh Well #2 Treatment (GW) | SE2 | 13.5 | 11.4 | 1.395 | PFBA 8.1, PFHpA 7, PFHxA 9.9, PFPeA 11, lithium 11.9 µg/L |
| 2025-02-03 | Loch Alsh Well #6 Treatment (GW) | SE2 | 10.5 | 11.6 | 0.434 | PFBA 5.1, PFHpA 3.8, PFHxA 5.1, PFPeA 4.8, lithium 10.2 µg/L |
| 2025-02-03 | Loch Alsh Well #7 Treatment (GW) | SE2 | 10.6 | 8.9 | 0.414 | PFHpA 5, PFHxA 5.8, PFPeA 5.6 |
| 2025-02-03 | Well #11 Treatment (GW) | SE2 | 12.2 | 8.3 | 0.883 | PFBA 6.3, PFHpA 6.7, PFHxA 9.2, PFPeA 9.9, lithium 14.1 µg/L |
| 2025-02-03 | Well #12 Treatment (GW) | SE2 | 8.2 | 5.9 | 0.003 | PFHpA 4.8, PFHxA 5.3, PFPeA 6.5, lithium 12.8 µg/L |
| 2025-02-03 | Well #14 Treatment (GW) | SE2 | 8.5 | 7.2 | 0.003 | PFHpA 4.5, PFHxA 6.5, PFPeA 6.1, lithium 12.6 µg/L |
| 2025-02-03 | Well #4 Treatment (GW) | SE2 | 11.1 | 8.5 | 0.334 | PFBA 5.8, PFHpA 5.2, PFHxA 6.7, PFPeA 7.4, lithium 13.6 µg/L |
| 2025-02-03 | Well #9 Treatment (GW) | SE2 | 15.3 | 11 | 0.374 | PFBA 5.7, PFHpA 6.4, PFHxA 7.4, PFPeA 7.6, lithium 22.4 µg/L |
| 2025-02-03 | Whitemarsh Spring Treatment (SW) | SE3 | <4 | <4 | 0.002 | PFBA 8.1, PFHxA 7.2, PFPeA 12.3 |
| 2025-03-11 | Loch Alsh Well #2 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-03-11 | Whitemarsh Spring Treatment (SW) | SE3 | n/a | n/a | n/a | none |
| 2025-04-29 | Loch Alsh Well #6 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-04-29 | Loch Alsh Well #7 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-04-29 | Well #11 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-04-29 | Well #14 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-04-29 | Well #4 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-04-29 | Well #9 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-05-13 | Well #12 Treatment (GW) | SE2 | n/a | n/a | n/a | none |
| 2025-05-13 | Whitemarsh Spring Treatment (SW) | SE4 | <4 | <4 | 0 | none |
“<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.
Loch Alsh Well #2 Treatment facility 00101 · sample point 101 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-03-11 SE2 |
|---|---|---|---|---|---|
| 6:2 FTS | 5 ppt | 6 | – | < 5 | – |
| PFBA | 5 ppt | 8 | – | 8.1 | – |
| PFBS | 3 ppt | 6.5 | – | 9.2 | – |
| PFHpA | 3 ppt | 9 | – | 7 | – |
| PFHxA | 3 ppt | 12.2 | – | 9.9 | – |
| PFHxS | 3 ppt | 4.4 | – | 4 | – |
| PFNA | 4 ppt | 13.5 | – | 9.9 | – |
| PFOA | 4 ppt | 14.2 | – | 13.5 | – |
| PFOS | 4 ppt | 12.4 | – | 11.4 | – |
| PFPeA | 3 ppt | 14 | – | 11 | – |
| 11Cl-PF3OUdS | 5 ppt | < 5 | – | < 5 | – |
| 4:2 FTS | 3 ppt | < 3 | – | < 3 | – |
| 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 | – |
| PFMBA | 3 ppt | < 3 | – | < 3 | – |
| PFMPA | 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 | 11.2 | – | 11.9 | – |
Loch Alsh Well #6 Treatment facility 00102 · sample point 102 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | < 5 | – | 5.1 | – |
| PFBS | 3 ppt | 6.2 | – | 7.5 | – |
| PFHpA | 3 ppt | 4.2 | – | 3.8 | – |
| PFHxA | 3 ppt | 6 | – | 5.1 | – |
| PFHxS | 3 ppt | 4.1 | – | 4.3 | – |
| PFOA | 4 ppt | 10 | – | 10.5 | – |
| PFOS | 4 ppt | 13.5 | – | 11.6 | – |
| PFPeA | 3 ppt | 5.5 | – | 4.8 | – |
| 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 | – |
| 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 | – | 10.2 | – |
Loch Alsh Well #7 Treatment facility 00103 · sample point 103 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 5.7 | – | < 5 | – |
| PFBS | 3 ppt | 9.2 | – | 9 | – |
| PFHpA | 3 ppt | 4.5 | – | 5 | – |
| PFHxA | 3 ppt | 5.8 | – | 5.8 | – |
| PFHxS | 3 ppt | 5 | – | 4.1 | – |
| PFOA | 4 ppt | 10.5 | – | 10.6 | – |
| PFOS | 4 ppt | 10.6 | – | 8.9 | – |
| PFPeA | 3 ppt | 5.6 | – | 5.6 | – |
| 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 | – |
| 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 | – |
Well #11 Treatment facility 00107 · sample point 107 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 6.7 | – | 6.3 | – |
| PFBS | 3 ppt | 7 | – | 6.7 | – |
| PFHpA | 3 ppt | 4.6 | – | 6.7 | – |
| PFHxA | 3 ppt | 7.9 | – | 9.2 | – |
| PFHxS | 3 ppt | 4.4 | – | 3.5 | – |
| PFNA | 4 ppt | < 4 | – | 5.3 | – |
| PFOA | 4 ppt | 10.4 | – | 12.2 | – |
| PFOS | 4 ppt | 8.6 | – | 8.3 | – |
| PFPeA | 3 ppt | 7.7 | – | 9.9 | – |
| 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 |
| 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 | – |
| PFPeS | 4 ppt | < 4 | – | < 4 | – |
| PFTA | 8 ppt | – | < 8 | – | < 8 |
| PFTrDA | 7 ppt | – | < 7 | – | < 7 |
| PFUnA | 2 ppt | < 2 | – | < 2 | – |
| lithium | 9 µg/L | 12.4 | – | 14.1 | – |
Well #12 Treatment facility 00108 · sample point 108 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-05-13 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 5 | – | < 5 | – |
| PFBS | 3 ppt | 6.7 | – | 6.3 | – |
| PFHpA | 3 ppt | 4.1 | – | 4.8 | – |
| PFHxA | 3 ppt | 7.5 | – | 5.3 | – |
| PFOA | 4 ppt | 8.7 | – | 8.2 | – |
| PFOS | 4 ppt | 8 | – | 5.9 | – |
| PFPeA | 3 ppt | 6.6 | – | 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 |
| 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 | 12 | – | 12.8 | – |
Well #14 Treatment facility 00110 · sample point 110 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 5.9 | – | < 5 | – |
| PFBS | 3 ppt | 8.1 | – | 6.5 | – |
| PFHpA | 3 ppt | 4.2 | – | 4.5 | – |
| PFHxA | 3 ppt | 9.5 | – | 6.5 | – |
| PFOA | 4 ppt | 9 | – | 8.5 | – |
| PFOS | 4 ppt | 9.5 | – | 7.2 | – |
| PFPeA | 3 ppt | 6.8 | – | 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 |
| 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 | 11.6 | – | 12.6 | – |
Well #4 Treatment facility 00105 · sample point 105 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 6.4 | – | 5.8 | – |
| PFBS | 3 ppt | 6.4 | – | 7.3 | – |
| PFHpA | 3 ppt | 4.2 | – | 5.2 | – |
| PFHxA | 3 ppt | 6 | – | 6.7 | – |
| PFHxS | 3 ppt | 3.7 | – | 3.3 | – |
| PFOA | 4 ppt | 10.2 | – | 11.1 | – |
| PFOS | 4 ppt | 9.8 | – | 8.5 | – |
| PFPeA | 3 ppt | 6.7 | – | 7.4 | – |
| 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 |
| 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 | 12.9 | – | 13.6 | – |
Well #9 Treatment facility 00106 · sample point 106 · groundwater
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2025-02-03 SE2 | 2025-04-29 SE2 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 6 | – | 5.7 | – |
| PFBS | 3 ppt | 8.2 | – | 8.5 | – |
| PFHpA | 3 ppt | 5.2 | – | 6.4 | – |
| PFHxA | 3 ppt | 7.6 | – | 7.4 | – |
| PFHxS | 3 ppt | 4.5 | – | 3.7 | – |
| PFOA | 4 ppt | 12.9 | – | 15.3 | – |
| PFOS | 4 ppt | 13.7 | – | 11 | – |
| PFPeA | 3 ppt | 6.9 | – | 7.6 | – |
| 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 | – |
| 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 | 21.9 | – | 22.4 | – |
Whitemarsh Spring Treatment facility 00109 · sample point 109 · surface water
| Compound | MRL | 2024-08-19 SE1 | 2024-09-09 SE1 | 2024-11-06 SE2 | 2025-02-03 SE3 | 2025-03-11 SE3 | 2025-05-13 SE4 |
|---|---|---|---|---|---|---|---|
| PFBA | 5 ppt | 7.1 | – | 10.6 | 8.1 | – | < 5 |
| PFBS | 3 ppt | < 3 | – | < 3 | 3.8 | – | < 3 |
| PFHxA | 3 ppt | < 3 | – | 4.5 | 7.2 | – | < 3 |
| PFPeA | 3 ppt | < 3 | – | 10.4 | 12.3 | – | < 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 |
| 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 |
| PFOA | 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 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| PFHxA | 20 | 90% | 12.2 2024-08-19 | 6.5–6.8 | 6.5 | 7.6 | 9.5 | 9.9 |
| PFPeA | 20 | 90% | 14 2024-08-19 | 7.07–7.37 | 6.7 | 7.7 | 11 | 12.3 |
| PFBS | 20 | 85% | 9.2 2024-08-19 | 6.16–6.61 | 6.7 | 8.1 | 9 | 9.2 |
| PFHpA | 20 | 80% | 9 2024-08-19 | 4.17–4.77 | 4.5 | 5.2 | 6.7 | 7 |
| PFOA | 20 | 80% | 15.3 2025-02-03 | 8.79–9.59 | 10.2 | 11.1 | 13.5 | 14.2 |
| PFOS | 20 | 80% | 13.7 2024-08-19 | 7.95–8.74 | 8.6 | 11 | 12.4 | 13.5 |
| PFBA | 20 | 75% | 10.6 2024-11-06 | 5.03–6.28 | 5.8 | 6.7 | 8.1 | 8.1 |
| lithium | 20 | 70% | 22.4 2025-02-03 | 9.47–12.18 | 11.6 | 12.8 | 14.1 | 21.9 |
| PFHxS | 20 | 60% | 5 2024-08-19 | 2.45–3.65 | 3.5 | 4.1 | 4.4 | 4.5 |
| PFNA | 20 | 15% | 13.5 2024-08-19 | 1.44–4.83 | <MRL | <MRL | 5.3 | 9.9 |
| 6:2 FTS | 20 | 5% | 6 2024-08-19 | 0.3–5.05 | <MRL | <MRL | <MRL | <MRL |
Never detected (19): 11Cl-PF3OUdS, 4:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFDA, PFDoA, PFEESA, PFHpS, PFMBA, PFMPA, PFPeS, PFTA, PFTrDA, PFUnA.
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 2023-01-10 to 2026-04-09; 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 52bd2907cbc3 · 2026-10-18T04:10Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.