- PWSID
- PA1460028
- State
- Pennsylvania
- System type
- community water system (CWS)
- Population served
- 12,901
- City
- Bryn Mawr
- Counties
- Montgomery County
- Primary source water
- surface water (purchased)
- UCMR 5 sampling
- 2024-01-30 to 2024-10-16 · 3 entry point(s) · water types: GW;MX
- Service-area boundary
- authoritative
PFOS ≥ 3 × its limit highest single result
PFOS ≥ 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
- 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) | 16.2 | 16.05 | 4 |
| PFOS (ppt) | 21.5 | 19.05 | 4 |
| Hazard Index | 0.625 | 0.59 | 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) | 16.2 | 16.05 | 14 |
| PFOS (ppt) | 21.5 | 19.05 | 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 2024-01-30 to 2024-10-16 · 3 entry point(s) · water types: GW;MX · 8 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2024-01-30 | Well #8 Treatment (GW) | SE1 | 16.2 | 21.5 | 0.625 | PFBA 6.5, PFHpA 5.5, PFHxA 8.7, PFPeA 9 |
| 2024-01-30 | Well #9 Treatment (GW) | SE1 | <4 | <4 | 0 | none |
| 2024-01-31 | Purchased Water Connection (MX) | SE1 | 6.2 | 5.8 | 0.362 | PFBA 7.6, PFHxA 6, PFPeA 6.2 |
| 2024-04-03 | Purchased Water Connection (MX) | SE2 | 6.6 | 5.7 | 0.352 | PFBA 5.4, PFHxA 6, PFPeA 6.1 |
| 2024-07-10 | Purchased Water Connection (MX) | SE3 | 8.8 | 6.6 | 0.473 | PFBA 8.2, PFHpA 3.8, PFHxA 11.8, PFPeA 16.1 |
| 2024-07-22 | Well #8 Treatment (GW) | SE2 | 15.9 | 16.6 | 0.555 | PFBA 7.2, PFHpA 5.7, PFHxA 9.6, PFPeA 10.4 |
| 2024-07-22 | Well #9 Treatment (GW) | SE2 | <4 | <4 | 0 | PFBA 7, PFPeA 3.3 |
| 2024-10-16 | Purchased Water Connection (MX) | SE4 | 6 | 4.6 | 0.362 | PFBA 5.5, PFHxA 8.6, PFPeA 13.3 |
“<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
240 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.
Purchased Water Connection facility 00116 · sample point 116 · MX
| Compound | MRL | 2024-01-31 SE1 | 2024-04-03 SE2 | 2024-07-10 SE3 | 2024-10-16 SE4 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | 7.6 | 5.4 | 8.2 | 5.5 |
| PFBS | 3 ppt | 4.9 | 4.8 | 5.9 | 5 |
| PFHpA | 3 ppt | < 3 | < 3 | 3.8 | < 3 |
| PFHxA | 3 ppt | 6 | 6 | 11.8 | 8.6 |
| PFHxS | 3 ppt | 3.6 | 3.5 | 4.7 | 3.6 |
| PFOA | 4 ppt | 6.2 | 6.6 | 8.8 | 6 |
| PFOS | 4 ppt | 5.8 | 5.7 | 6.6 | 4.6 |
| PFPeA | 3 ppt | 6.2 | 6.1 | 16.1 | 13.3 |
| 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 |
| 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 |
Well #8 Treatment facility 00103 · sample point 103 · groundwater
| Compound | MRL | 2024-01-30 SE1 | 2024-07-22 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 6.5 | 7.2 |
| PFBS | 3 ppt | 10.4 | 11 |
| PFHpA | 3 ppt | 5.5 | 5.7 |
| PFHxA | 3 ppt | 8.7 | 9.6 |
| PFHxS | 3 ppt | 6.2 | 5.5 |
| PFOA | 4 ppt | 16.2 | 15.9 |
| PFOS | 4 ppt | 21.5 | 16.6 |
| PFPeA | 3 ppt | 9 | 10.4 |
| 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 | < 9 | < 9 |
Well #9 Treatment facility 00104 · sample point 104 · groundwater
| Compound | MRL | 2024-01-30 SE1 | 2024-07-22 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 7 |
| PFPeA | 3 ppt | < 3 | 3.3 |
| 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 |
| 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 |
| 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 |
|---|---|---|---|---|---|---|---|---|
| PFBA | 8 | 88% | 8.2 2024-07-10 | 5.92–6.55 | 6.5 | 7.2 | 8.2 | 8.2 |
| PFPeA | 8 | 88% | 16.1 2024-07-10 | 8.05–8.43 | 6.2 | 10.4 | 16.1 | 16.1 |
| PFBS | 8 | 75% | 11 2024-07-22 | 5.25–6 | 4.9 | 5.9 | 11 | 11 |
| PFHxA | 8 | 75% | 11.8 2024-07-10 | 6.34–7.09 | 6 | 8.7 | 11.8 | 11.8 |
| PFHxS | 8 | 75% | 6.2 2024-01-30 | 3.39–4.14 | 3.6 | 4.7 | 6.2 | 6.2 |
| PFOA | 8 | 75% | 16.2 2024-01-30 | 7.46–8.46 | 6.2 | 8.8 | 16.2 | 16.2 |
| PFOS | 8 | 75% | 21.5 2024-01-30 | 7.6–8.6 | 5.7 | 6.6 | 21.5 | 21.5 |
| PFHpA | 8 | 38% | 5.7 2024-07-22 | 1.88–3.75 | <MRL | 3.8 | 5.7 | 5.7 |
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 2023-01-10 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.