- PWSID
- CA1910042
- State
- California
- System type
- community water system (CWS)
- Population served
- 39,451
- City
- Pico Rivera
- Counties
- Los Angeles County
- Primary source water
- groundwater
- UCMR 5 sampling
- 2024-02-28 to 2024-08-28 · 8 entry point(s) · water types: GW
- Service-area boundary
- authoritative
PFOS ≥ 3 × its limit highest single result
PFOS ≥ 3 × its limit worst entry-point average
Open on the California map · All California 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) | 16 | 12.6 | 4 |
| PFOS (ppt) | 30 | 29 | 4 |
| Hazard Index | 0.565 | 0.525 | 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 California guidance levels
| Highest single result | Worst entry-point average* | California | |
|---|---|---|---|
| PFHxS (ppt) | 5.6 | 5.2 | 3 (guidance) |
| PFOA (ppt) | 16 | 12.6 | 4 (guidance) |
| PFOS (ppt) | 30 | 29 | 4 (guidance) |
| PFBS (ppt) | 10 | 9.7 | 500 (guidance) |
| PFHxA (ppt) | 15 | 12.5 | 1,000 (guidance) |
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 2024-02-28 to 2024-08-28 · 8 entry point(s) · water types: GW · 15 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2024-02-28 | Well W11 (GW) | SE1 | 7.2 | 10 | 0.003 | PFBA 7, PFHxA 13, PFPeA 16 |
| 2024-02-28 | Well W12 (GW) | SE1 | 7.6 | 9.8 | 0.003 | PFBA 7.1, PFHxA 14, PFPeA 16 |
| 2024-02-28 | Well W2 (GW) | SE1 | 9.2 | 27 | 0.485 | PFBA 14, PFHxA 3.3, PFPeA 3.8 |
| 2024-02-28 | Well W3 (GW) | SE1 | 8.6 | 13 | 0.002 | PFDA 5.1, PFHpA 3.2, PFHxA 9, PFPeA 9.8 |
| 2024-02-28 | Well W4 (GW) | SE1 | 7.7 | 11 | 0.002 | PFDA 5.6, PFHxA 9.2, PFPeA 8.9 |
| 2024-02-28 | Well W5 (GW) | SE1 | 9.7 | 23 | 0.003 | PFBA 5.2, PFHpA 3.2, PFHxA 9.6, PFPeA 10 |
| 2024-02-28 | Well W6 (GW) | SE1 | 11 | 17 | 0.313 | PFBA 6.1, PFHpA 4.1, PFHxA 15, PFPeA 17 |
| 2024-08-28 | Well W1 (GW) | SE2 | 7.6 | 29 | 0.334 | PFBA 12 |
| 2024-08-28 | Well W11 (GW) | SE2 | 6.6 | 9.8 | 0.002 | PFBA 5.5, PFHxA 11, PFPeA 13 |
| 2024-08-28 | Well W12 (GW) | SE2 | 5.8 | 9.8 | 0.002 | PFBA 5.5, PFHxA 11, PFPeA 14 |
| 2024-08-28 | Well W2 (GW) | SE2 | 16 | 30 | 0.565 | PFBA 14, PFHpA 4.1, PFHxA 5.8, PFPeA 6.7 |
| 2024-08-28 | Well W3 (GW) | SE2 | 7.5 | 14 | 0.002 | PFDA 4.1, PFHxA 6.7, PFPeA 7.4 |
| 2024-08-28 | Well W4 (GW) | SE2 | 7.7 | 13 | 0.002 | PFDA 4.7, PFHxA 7.8, PFPeA 7.9 |
| 2024-08-28 | Well W5 (GW) | SE2 | <4 | <4 | 0 | none |
| 2024-08-28 | Well W6 (GW) | SE2 | 8.7 | 19 | 0.002 | PFHxA 7.7, PFPeA 8.5 |
“<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
450 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 W1 facility 00002 · sample point 2 · groundwater
| Compound | MRL | 2024-08-28 SE2 |
|---|---|---|
| PFBA | 5 ppt | 12 |
| PFBS | 3 ppt | 8.8 |
| PFHxS | 3 ppt | 3.3 |
| PFOA | 4 ppt | 7.6 |
| PFOS | 4 ppt | 29 |
| 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 |
| PFHpA | 3 ppt | < 3 |
| PFHpS | 3 ppt | < 3 |
| PFHxA | 3 ppt | < 3 |
| PFMBA | 3 ppt | < 3 |
| PFMPA | 4 ppt | < 4 |
| PFNA | 4 ppt | < 4 |
| PFPeA | 3 ppt | < 3 |
| PFPeS | 4 ppt | < 4 |
| PFTA | 8 ppt | < 8 |
| PFTrDA | 7 ppt | < 7 |
| PFUnA | 2 ppt | < 2 |
| lithium | 9 µg/L | < 9 |
Well W11 facility 00004 · sample point 4 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 7 | 5.5 |
| PFBS | 3 ppt | 6.3 | 4.2 |
| PFHxA | 3 ppt | 13 | 11 |
| PFOA | 4 ppt | 7.2 | 6.6 |
| PFOS | 4 ppt | 10 | 9.8 |
| PFPeA | 3 ppt | 16 | 13 |
| 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 |
| 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 | < 9 | < 9 |
Well W12 facility 00005 · sample point 5 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 7.1 | 5.5 |
| PFBS | 3 ppt | 6.8 | 4.4 |
| PFHxA | 3 ppt | 14 | 11 |
| PFOA | 4 ppt | 7.6 | 5.8 |
| PFOS | 4 ppt | 9.8 | 9.8 |
| PFPeA | 3 ppt | 16 | 14 |
| 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 |
| 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 | < 9 | < 9 |
Well W2 facility 00006 · sample point 6 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 14 | 14 |
| PFBS | 3 ppt | 10 | 9.4 |
| PFHpA | 3 ppt | < 3 | 4.1 |
| PFHxA | 3 ppt | 3.3 | 5.8 |
| PFHxS | 3 ppt | 4.8 | 5.6 |
| PFOA | 4 ppt | 9.2 | 16 |
| PFOS | 4 ppt | 27 | 30 |
| PFPeA | 3 ppt | 3.8 | 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 |
| 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 W3 facility 00007 · sample point 7 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 4.6 | 3.5 |
| PFDA | 3 ppt | 5.1 | 4.1 |
| PFHpA | 3 ppt | 3.2 | < 3 |
| PFHxA | 3 ppt | 9 | 6.7 |
| PFOA | 4 ppt | 8.6 | 7.5 |
| PFOS | 4 ppt | 13 | 14 |
| PFPeA | 3 ppt | 9.8 | 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 |
| PFBA | 5 ppt | < 5 | < 5 |
| 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 |
Well W4 facility 00008 · sample point 8 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 4.8 | 4.1 |
| PFDA | 3 ppt | 5.6 | 4.7 |
| PFHxA | 3 ppt | 9.2 | 7.8 |
| PFOA | 4 ppt | 7.7 | 7.7 |
| PFOS | 4 ppt | 11 | 13 |
| PFPeA | 3 ppt | 8.9 | 7.9 |
| 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 |
| 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 | < 9 | < 9 |
Well W5 facility 00009 · sample point 9 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5.2 | < 5 |
| PFBS | 3 ppt | 5.8 | < 3 |
| PFHpA | 3 ppt | 3.2 | < 3 |
| PFHxA | 3 ppt | 9.6 | < 3 |
| PFOA | 4 ppt | 9.7 | < 4 |
| PFOS | 4 ppt | 23 | < 4 |
| PFPeA | 3 ppt | 10 | < 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 |
| 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 |
Well W6 facility 00010 · sample point 10 · groundwater
| Compound | MRL | 2024-02-28 SE1 | 2024-08-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 6.1 | < 5 |
| PFBS | 3 ppt | 6.7 | 3.9 |
| PFHpA | 3 ppt | 4.1 | < 3 |
| PFHxA | 3 ppt | 15 | 7.7 |
| PFHxS | 3 ppt | 3.1 | < 3 |
| PFOA | 4 ppt | 11 | 8.7 |
| PFOS | 4 ppt | 17 | 19 |
| PFPeA | 3 ppt | 17 | 8.5 |
| 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 |
| 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 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| PFBS | 15 | 93% | 10 2024-02-28 | 5.55–5.75 | 4.8 | 6.8 | 9.4 | 10 |
| PFOA | 15 | 93% | 16 2024-08-28 | 8.06–8.33 | 7.7 | 9.2 | 11 | 16 |
| PFOS | 15 | 93% | 30 2024-08-28 | 15.69–15.96 | 13 | 23 | 29 | 30 |
| PFHxA | 15 | 87% | 15 2024-02-28 | 8.21–8.61 | 9 | 11 | 14 | 15 |
| PFPeA | 15 | 87% | 17 2024-02-28 | 9.27–9.67 | 8.9 | 14 | 16 | 17 |
| PFBA | 15 | 60% | 14 2024-02-28 | 5.09–7.09 | 5.5 | 7.1 | 14 | 14 |
| PFDA | 15 | 27% | 5.6 2024-02-28 | 1.3–3.5 | <MRL | 4.1 | 5.1 | 5.6 |
| PFHpA | 15 | 27% | 4.1 2024-02-28 | 0.97–3.17 | <MRL | 3.2 | 4.1 | 4.1 |
| PFHxS | 15 | 27% | 5.6 2024-08-28 | 1.12–3.32 | <MRL | 3.1 | 4.8 | 5.6 |
Never detected (21): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, 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 2023-01-09 to 2026-06-17; 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 90f0922cd84f · 2026-10-18T04:12Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.