ST. HELENA, CITY OF
PWS ID: CA2810004 · ST. HELENA, California 94574
PFAS Detected
1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
5,386
Total Violations
23
Health-Based Violations
19
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 2,551
- County
- Napa
- School/Daycare
- No
- MCL Violations
- 15
- Monitoring Violations
- 1
- Treatment Tech Violations
- 4
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Total Haloacetic Acids (HAA5) | MCL | 13 | 2023 |
| Surface Water Treatment Rule | TT | 4 | 2020 |
| Coliform (TCR) | MCL | 2 | 1995 |
| Lead and Copper Rule | MR | 1 | 2022 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 2 of 300 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHpS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| lithium | 7/12/2023 | <9 µg/L | 9 µg/L | Not Detected |
| HFPO-DA | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 7/12/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 7/12/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| NFDHA | 7/12/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFDoA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NEtFOSAA | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTrDA | 7/12/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 7/12/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFPeS | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFEESA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 7/12/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFHxA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFMBA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 7/12/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| NEtFOSAA | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 7/12/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 7/12/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| lithium | 7/12/2023 | 54.0000 µg/L | 9 µg/L | Detected |
| PFOS | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 7/12/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFMPA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeS | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 7/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 7/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 7/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025.
PFAS data from EPA UCMR5 monitoring program (2023-2025).
This data is provided for informational purposes only.