- PWSID
- PA1460022
- State
- Pennsylvania
- System type
- community water system (CWS)
- Population served
- 8,470
- City
- Trappe
- Counties
- Montgomery County
- Primary source water
- groundwater
- UCMR 5 sampling
- 2023-03-20 to 2023-09-20 · 7 entry point(s) · water types: GW
- 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.
Compared with EPA's 2024 values
| Highest single result | Worst entry-point average* | Limit | |
|---|---|---|---|
| PFOA (ppt) | 235 | 235 | 4 |
| PFOS (ppt) | 15 | 15 | 4 |
| Hazard Index | 0.422 | 0.417 | 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) | 235 | 235 | 14 |
| PFOS (ppt) | 15 | 15 | 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 2023-03-20 to 2023-09-20 · 7 entry point(s) · water types: GW · 13 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2023-03-20 | WELL 14 (GW) | SE1 | 14.9 | 9.3 | 0.422 | PFBA 5.2, PFHpA 3, PFHxA 4.8, PFPeA 4.8, lithium 37 µg/L |
| 2023-03-20 | WELL 8 (GW) | SE1 | 7.7 | 9.6 | 0.002 | PFHxA 3.2, PFPeA 3.1, lithium 17.3 µg/L |
| 2023-03-21 | WELL 1,3,4,7 (GW) | SE1 | 7.2 | 9.3 | 0.003 | PFHxA 3.6, PFPeA 3.7, lithium 11.4 µg/L |
| 2023-03-21 | WELL 10 (GW) | SE1 | 8.6 | 9 | 0.007 | PFBA 5, PFHpA 3.7, PFHxA 5.3, PFPeA 5.8, lithium 19.1 µg/L |
| 2023-03-21 | WELL 5 (GW) | SE1 | 6.5 | 6.8 | 0.008 | PFHxA 3.3, PFPeA 3.3 |
| 2023-03-22 | WELL 11 (GW) | SE1 | 235 | 15 | 0.312 | PFBA 6.6, PFHpA 6.2, PFHxA 10.9, PFPeA 7.4, lithium 21.8 µg/L |
| 2023-03-22 | WELL 12 (GW) | SE1 | 10.7 | 9.7 | 0.004 | PFBA 5, PFHpA 4.1, PFHxA 6.3, PFPeA 6.5, lithium 22.2 µg/L |
| 2023-09-18 | WELL 1,3,4,7 (GW) | SE2 | 8.2 | 7.1 | 0.003 | PFHpA 3.2, PFHxA 4.8, PFPeA 5.9, lithium 12 µg/L |
| 2023-09-18 | WELL 12 (GW) | SE2 | 15 | 11 | 0.003 | PFHpA 5.5, PFHxA 7.6, PFPeA 8.4, lithium 17 µg/L |
| 2023-09-18 | WELL 14 (GW) | SE2 | 17 | 10 | 0.412 | PFHpA 3.5, PFHxA 5.2, PFPeA 5.7, lithium 31 µg/L |
| 2023-09-18 | WELL 8 (GW) | SE2 | 12 | 12 | 0.002 | PFHpA 4, PFHxA 5.1, PFPeA 5.5, lithium 14 µg/L |
| 2023-09-20 | WELL 10 (GW) | SE2 | 8.9 | 9.3 | 0.006 | PFHpA 3.7, PFHxA 5.5, PFPeA 6.7, lithium 16 µg/L |
| 2023-09-20 | WELL 5 (GW) | SE2 | 11 | 8.3 | 0.007 | PFBA 6.3, PFHpA 4.7, PFHxA 7, PFPeA 5.9, lithium 10 µg/L |
“<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
390 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.
WELL 1,3,4,7 facility 101 · sample point E · groundwater
| Compound | MRL | 2023-03-21 SE1 | 2023-09-18 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 6.1 | 5.3 |
| PFHpA | 3 ppt | < 3 | 3.2 |
| PFHxA | 3 ppt | 3.6 | 4.8 |
| PFOA | 4 ppt | 7.2 | 8.2 |
| PFOS | 4 ppt | 9.3 | 7.1 |
| PFPeA | 3 ppt | 3.7 | 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 |
| 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 | 11.4 | 12 |
WELL 10 facility 106 · sample point E · groundwater
| Compound | MRL | 2023-03-21 SE1 | 2023-09-20 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5 | < 5 |
| PFBS | 3 ppt | 13.8 | 12 |
| PFHpA | 3 ppt | 3.7 | 3.7 |
| PFHxA | 3 ppt | 5.3 | 5.5 |
| PFOA | 4 ppt | 8.6 | 8.9 |
| PFOS | 4 ppt | 9 | 9.3 |
| PFPeA | 3 ppt | 5.8 | 6.7 |
| 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 | 19.1 | 16 |
WELL 11 facility 107 · sample point E · groundwater
| Compound | MRL | 2023-03-22 SE1 |
|---|---|---|
| PFBA | 5 ppt | 6.6 |
| PFBS | 3 ppt | 4.8 |
| PFHpA | 3 ppt | 6.2 |
| PFHxA | 3 ppt | 10.9 |
| PFHxS | 3 ppt | 3.1 |
| PFOA | 4 ppt | 235 |
| PFOS | 4 ppt | 15 |
| PFPeA | 3 ppt | 7.4 |
| 11Cl-PF3OUdS | 5 ppt | < 5 |
| 4:2 FTS | 3 ppt | < 3 |
| 6:2 FTS | 5 ppt | < 5 |
| 8:2 FTS | 5 ppt | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 |
| ADONA | 3 ppt | < 3 |
| HFPO-DA | 5 ppt | < 5 |
| NEtFOSAA | 5 ppt | < 5 |
| NFDHA | 20 ppt | < 20 |
| NMeFOSAA | 6 ppt | < 6 |
| PFDA | 3 ppt | < 3 |
| PFDoA | 3 ppt | < 3 |
| PFEESA | 3 ppt | < 3 |
| PFHpS | 3 ppt | < 3 |
| PFMBA | 3 ppt | < 3 |
| PFMPA | 4 ppt | < 4 |
| PFNA | 4 ppt | < 4 |
| PFPeS | 4 ppt | < 4 |
| PFTA | 8 ppt | < 8 |
| PFTrDA | 7 ppt | < 7 |
| PFUnA | 2 ppt | < 2 |
| lithium | 9 µg/L | 21.8 |
WELL 12 facility 108 · sample point E · groundwater
| Compound | MRL | 2023-03-22 SE1 | 2023-09-18 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5 | < 5 |
| PFBS | 3 ppt | 7 | 5.6 |
| PFHpA | 3 ppt | 4.1 | 5.5 |
| PFHxA | 3 ppt | 6.3 | 7.6 |
| PFOA | 4 ppt | 10.7 | 15 |
| PFOS | 4 ppt | 9.7 | 11 |
| PFPeA | 3 ppt | 6.5 | 8.4 |
| 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 |
| 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 | 22.2 | 17 |
WELL 14 facility 109 · sample point E · groundwater
| Compound | MRL | 2023-03-20 SE1 | 2023-09-18 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5.2 | < 5 |
| PFBS | 3 ppt | 4.1 | 4 |
| PFHpA | 3 ppt | 3 | 3.5 |
| PFHxA | 3 ppt | 4.8 | 5.2 |
| PFHxS | 3 ppt | 4.2 | 4.1 |
| PFOA | 4 ppt | 14.9 | 17 |
| PFOS | 4 ppt | 9.3 | 10 |
| PFPeA | 3 ppt | 4.8 | 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 |
| 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 | 37 | 31 |
WELL 5 facility 102 · sample point E · groundwater
| Compound | MRL | 2023-03-21 SE1 | 2023-09-20 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 6.3 |
| PFBS | 3 ppt | 15.3 | 14 |
| PFHpA | 3 ppt | < 3 | 4.7 |
| PFHxA | 3 ppt | 3.3 | 7 |
| PFOA | 4 ppt | 6.5 | 11 |
| PFOS | 4 ppt | 6.8 | 8.3 |
| PFPeA | 3 ppt | 3.3 | 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 |
| 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 | 10 |
WELL 8 facility 104 · sample point E · groundwater
| Compound | MRL | 2023-03-20 SE1 | 2023-09-18 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 3.6 | 3.9 |
| PFHpA | 3 ppt | < 3 | 4 |
| PFHxA | 3 ppt | 3.2 | 5.1 |
| PFOA | 4 ppt | 7.7 | 12 |
| PFOS | 4 ppt | 9.6 | 12 |
| PFPeA | 3 ppt | 3.1 | 5.5 |
| 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 |
| 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 | 17.3 | 14 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| PFBS | 13 | 100% | 15.3 2023-03-21 | 7.65–7.65 | 5.6 | 12 | 14 | 15.3 |
| PFHxA | 13 | 100% | 10.9 2023-03-22 | 5.58–5.58 | 5.2 | 6.3 | 7.6 | 10.9 |
| PFOA | 13 | 100% | 235 2023-03-22 | 27.9–27.9 | 10.7 | 14.9 | 17 | 235 |
| PFOS | 13 | 100% | 15 2023-03-22 | 9.72–9.72 | 9.3 | 10 | 12 | 15 |
| PFPeA | 13 | 100% | 8.4 2023-09-18 | 5.59–5.59 | 5.8 | 6.5 | 7.4 | 8.4 |
| lithium | 13 | 92% | 37 2023-03-20 | 17.6–18.29 | 17 | 21.8 | 31 | 37 |
| PFHpA | 13 | 77% | 6.2 2023-03-22 | 3.2–3.89 | 3.7 | 4.1 | 5.5 | 6.2 |
| PFBA | 13 | 38% | 6.6 2023-03-22 | 2.16–5.24 | <MRL | 5 | 6.3 | 6.6 |
| PFHxS | 13 | 23% | 4.2 2023-03-20 | 0.88–3.18 | <MRL | <MRL | 4.1 | 4.2 |
Never detected (21): 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.
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.