ATASCADERO MUTUAL WATER CO
PWS ID: CA4010002 · ATASCADERO, California 93422
PFAS Detected
6 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
30,618
Total Violations
3
Health-Based Violations
2
Water Source
Groundwater
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 10,961
- County
- San Luis Obispo
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 0
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Surface Water Treatment Rule | TT | 2 | 1993 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 24 of 240 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFNA | 5/30/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 6:2 FTS | 5/30/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBS | 5/30/2023 | 0.0039 µg/L | 0.003 µg/L | Detected |
| PFHpA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxS | 5/30/2023 | 0.0043 µg/L | 0.003 µg/L | Detected |
| PFOS | 5/30/2023 | 0.0210 µg/L | 0.004 µg/L | Detected |
| PFDA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 5/30/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 5/30/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 9Cl-PF3ONS | 5/30/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOA | 5/30/2023 | 0.0084 µg/L | 0.004 µg/L | Detected |
| PFBA | 5/30/2023 | 0.0074 µg/L | 0.005 µg/L | Detected |
| NFDHA | 5/30/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| HFPO-DA | 5/30/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFPeS | 5/30/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFEESA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 5/30/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 5/30/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 5/30/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 8:2 FTS | 4/19/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 4/19/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFMBA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 4/19/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFMPA | 4/19/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 4/19/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFTrDA | 4/19/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 4/19/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| 6:2 FTS | 4/19/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOS | 4/19/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NEtFOSAA | 4/19/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFDoA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 4/19/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| lithium | 4/19/2023 | 11.9000 µg/L | 9 µg/L | Detected |
| PFBS | 4/19/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxS | 4/19/2023 | 0.0032 µg/L | 0.003 µg/L | Detected |
| PFNA | 4/19/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 4/19/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxA | 4/19/2023 | <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.