- PWSID
- MD0150002
- State
- Maryland
- System type
- community water system (CWS)
- Population served
- 6,005
- City
- Poolesville
- Counties
- Montgomery County
- Primary source water
- groundwater under the influence of surface water
- UCMR 5 sampling
- 2023-02-07 to 2025-11-10 · 9 entry point(s) · water types: GU;GW
- Service-area boundary
- authoritative
PFOS 1–3 × its limit highest single result
PFOS 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) | 5.4 | 5.3 | 4 |
| PFOS (ppt) | 6.5 | 6.05 | 4 |
| Hazard Index | 0.69 | 0.685 | 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 2025-11-10 · 9 entry point(s) · water types: GU;GW · 20 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | 4.1 | 4.5 | 0.002 | PFHxA 3.8, PFPeA 3.8, lithium 15.8 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | 5.1 | 5.6 | 0.002 | PFHxA 3.9, PFPeA 4.8, lithium 19.5 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | 5.4 | 5.3 | 0.002 | PFBA 7, PFHpA 5.1, PFHxA 9.8, PFPeA 14, lithium 18.5 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | <4 | <4 | 0 | lithium 38.8 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | 4.7 | <4 | 0 | lithium 38.8 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | <4 | <4 | 0 | lithium 15.1 µg/L |
| 2023-02-07 | TOWN OF POOLESVILLE (GW) | SE1 | <4 | 5.4 | 0.69 | lithium 18 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | 4.8 | 6 | 0.002 | PFHxA 3.5, PFPeA 3.8, lithium 16.2 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | 5.4 | 6.5 | 0.002 | PFHxA 3.7, PFPeA 4.3, lithium 21 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | 5.2 | <4 | 0.002 | PFBA 7, PFHpA 5.4, PFHxA 9.8, PFPeA 15.1, lithium 21.3 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | <4 | <4 | 0 | lithium 41.1 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | 5.3 | <4 | 0 | lithium 36 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | <4 | <4 | 0 | lithium 15.1 µg/L |
| 2023-08-08 | TOWN OF POOLESVILLE (GW) | SE2 | 4.1 | 6.5 | 0.68 | lithium 19 µg/L |
| 2023-12-05 | TOWN OF POOLESVILLE (GW) | SE1 | <4 | <4 | 0 | lithium 11 µg/L |
| 2024-03-11 | TOWN OF POOLESVILLE (GW) | SE2 | <4 | <4 | 0 | PFBA 8.9, lithium 12.3 µg/L |
| 2025-05-20 | Well #2 (GUDI) (GU) | SE1 | n/a | n/a | n/a | lithium 14 µg/L |
| 2025-07-23 | Well #2 (GUDI) (GU) | SE1 | <4 | <4 | 0 | none |
| 2025-09-22 | Well #2 (GUDI) (GU) | SE2 | <4 | <4 | 0 | lithium 15 µg/L |
| 2025-11-10 | Well #2 (GUDI) (GU) | SE4 | <4 | <4 | 0 | PFBA 7.7, lithium 15 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
570 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 POOLESVILLE facility TP03 · sample point EP03 · groundwater
| Compound | MRL | 2023-12-05 SE1 | 2024-03-11 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 8.9 |
| 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 |
| 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 | 11 | 12.3 |
TOWN OF POOLESVILLE facility TP05 · sample point EP05 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 3.1 | 3.2 |
| PFHxA | 3 ppt | 3.8 | 3.5 |
| PFOA | 4 ppt | 4.1 | 4.8 |
| PFOS | 4 ppt | 4.5 | 6 |
| PFPeA | 3 ppt | 3.8 | 3.8 |
| 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 |
| 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 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 15.8 | 16.2 |
TOWN OF POOLESVILLE facility TP06 · sample point EP06 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 3.6 | 4 |
| PFHxA | 3 ppt | 3.9 | 3.7 |
| PFOA | 4 ppt | 5.1 | 5.4 |
| PFOS | 4 ppt | 5.6 | 6.5 |
| PFPeA | 3 ppt | 4.8 | 4.3 |
| 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 |
| 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 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 19.5 | 21 |
TOWN OF POOLESVILLE facility TP08 · sample point EP08 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 7 | 7 |
| PFBS | 3 ppt | 4.8 | 4.2 |
| PFHpA | 3 ppt | 5.1 | 5.4 |
| PFHxA | 3 ppt | 9.8 | 9.8 |
| PFOA | 4 ppt | 5.4 | 5.2 |
| PFOS | 4 ppt | 5.3 | < 4 |
| PFPeA | 3 ppt | 14 | 15.1 |
| 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 | 18.5 | 21.3 |
TOWN OF POOLESVILLE facility TP09 · sample point EP09 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 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 | 38.8 | 41.1 |
TOWN OF POOLESVILLE facility TP10 · sample point EP10 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 SE2 |
|---|---|---|---|
| PFOA | 4 ppt | 4.7 | 5.3 |
| 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 |
| 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 |
| 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 | 38.8 | 36 |
TOWN OF POOLESVILLE facility TP12 · sample point EP12 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 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 | 15.1 | 15.1 |
TOWN OF POOLESVILLE facility TP13 · sample point EP13 · groundwater
| Compound | MRL | 2023-02-07 SE1 | 2023-08-08 SE2 |
|---|---|---|---|
| PFHxS | 3 ppt | 6.9 | 6.8 |
| PFOA | 4 ppt | < 4 | 4.1 |
| PFOS | 4 ppt | 5.4 | 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 |
| 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 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 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 | 18 | 19 |
Well #2 (GUDI) facility TP02 · sample point TP02 · groundwater under the influence of surface water
| Compound | MRL | 2025-05-20 SE1 | 2025-07-23 SE1 | 2025-09-22 SE2 | 2025-11-10 SE4 |
|---|---|---|---|---|---|
| PFBA | 5 ppt | – | < 5 | < 5 | 7.7 |
| 11Cl-PF3OUdS | 5 ppt | – | < 5 | < 5 | < 5 |
| 4:2 FTS | 3 ppt | – | < 3 | < 3 | < 3 |
| 6:2 FTS | 5 ppt | – | < 5 | < 5 | < 5 |
| 8:2 FTS | 5 ppt | – | < 5 | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | – | < 2 | < 2 | < 2 |
| ADONA | 3 ppt | – | < 3 | < 3 | < 3 |
| HFPO-DA | 5 ppt | – | < 5 | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | – | < 5 | < 5 |
| NFDHA | 20 ppt | – | < 20 | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | – | < 6 | < 6 |
| PFBS | 3 ppt | – | < 3 | < 3 | < 3 |
| PFDA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFDoA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFEESA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFHpA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFHpS | 3 ppt | – | < 3 | < 3 | < 3 |
| PFHxA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFHxS | 3 ppt | – | < 3 | < 3 | < 3 |
| PFMBA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFMPA | 4 ppt | – | < 4 | < 4 | < 4 |
| PFNA | 4 ppt | – | < 4 | < 4 | < 4 |
| PFOA | 4 ppt | – | < 4 | < 4 | < 4 |
| PFOS | 4 ppt | – | < 4 | < 4 | < 4 |
| PFPeA | 3 ppt | – | < 3 | < 3 | < 3 |
| PFPeS | 4 ppt | – | < 4 | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | – | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | – | < 7 | < 7 |
| PFUnA | 2 ppt | – | < 2 | < 2 | < 2 |
| lithium | 9 µg/L | 14 | – | 15 | 15 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| lithium | 19 | 100% | 41.1 2023-08-08 | 21.13–21.13 | 18 | 21.3 | 38.8 | 41.1 |
| PFOA | 19 | 47% | 5.4 2023-02-07 | 2.32–4.43 | <MRL | 5.1 | 5.4 | 5.4 |
| PFOS | 19 | 37% | 6.5 2023-08-08 | 2.09–4.62 | <MRL | 5.4 | 6.5 | 6.5 |
| PFBS | 19 | 32% | 4.8 2023-02-07 | 1.21–3.26 | <MRL | 3.2 | 4.2 | 4.8 |
| PFHxA | 19 | 32% | 9.8 2023-02-07 | 1.82–3.87 | <MRL | 3.7 | 9.8 | 9.8 |
| PFPeA | 19 | 32% | 15.1 2023-08-08 | 2.41–4.46 | <MRL | 3.8 | 14 | 15.1 |
| PFBA | 19 | 21% | 8.9 2024-03-11 | 1.61–5.56 | <MRL | <MRL | 7.7 | 8.9 |
| PFHpA | 19 | 10% | 5.4 2023-08-08 | 0.55–3.24 | <MRL | <MRL | 5.1 | 5.4 |
| PFHxS | 19 | 10% | 6.9 2023-02-07 | 0.72–3.41 | <MRL | <MRL | 6.8 | 6.9 |
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 2023-01-04 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.