DIABLO WATER DISTRICT
PWS ID: CA0710007 · OAKLEY, California 94561
PFAS Detected
1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
43,357
Total Violations
0
Health-Based Violations
0
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 13,617
- County
- Contra Costa
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 0
- Treatment Tech Violations
- 0
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 3 of 95 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHpS | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 9/29/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 9/29/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 4:2 FTS | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 9/29/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxS | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 9/29/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 9/29/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 11Cl-PF3OUdS | 9/29/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFDA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 9/29/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFPeA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 9/29/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 9Cl-PF3ONS | 9/29/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 9/29/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 9/29/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 9/29/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 9/29/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 9/29/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NEtFOSAA | 9/11/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 9/11/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NMeFOSAA | 9/11/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| lithium | 9/11/2023 | 13.0000 µg/L | 9 µg/L | Detected |
| PFTA | 9/11/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| NEtFOSAA | 6/1/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| lithium | 6/1/2023 | 13.0000 µg/L | 9 µg/L | Detected |
| NMeFOSAA | 6/1/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFTrDA | 6/1/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 6/1/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFTA | 3/30/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| NMeFOSAA | 3/30/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| NEtFOSAA | 3/30/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 3/30/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NFDHA | 3/16/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| ADONA | 3/16/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 3/16/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 3/16/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 6:2 FTS | 3/16/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 3/16/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 8:2 FTS | 3/16/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFMPA | 3/16/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeA | 3/16/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 3/16/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 3/16/2023 | <0.003 µg/L | 0.003 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.