GUADALUPE VALLEY MID
PWS ID: CA4110005 · BRISBANE, California 94005
PFAS Detected
6 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
1,472
Total Violations
8
Health-Based Violations
2
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 749
- County
- San Mateo
- School/Daycare
- No
- MCL Violations
- 0
- Monitoring Violations
- 4
- Treatment Tech Violations
- 2
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Lead and Copper Rule | MR | 2 | 2004 |
| Surface Water Treatment Rule | TT | 2 | 1993 |
| Coliform (TCR) | MR | 2 | 1999 |
| Coliform (TCR) | Other | 2 | 1999 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 6 of 120 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFHxA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 9/12/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFPeA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 9/12/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFMPA | 9/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDoA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOA | 9/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 9/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 9/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 11Cl-PF3OUdS | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 9/12/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFPeS | 9/12/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 9/12/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 4:2 FTS | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NEtFOSAA | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 8:2 FTS | 9/12/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTA | 9/12/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| lithium | 9/12/2023 | <9 µg/L | 9 µg/L | Not Detected |
| PFHpS | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 9/12/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 9/12/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| lithium | 6/6/2023 | <9 µg/L | 9 µg/L | Not Detected |
| PFTrDA | 6/6/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 6/6/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| NEtFOSAA | 6/6/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NMeFOSAA | 6/6/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFHxA | 3/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 3/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 3/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 3/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 3/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 3/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 3/7/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxS | 3/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 3/7/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFBS | 3/7/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 3/7/2023 | <9 µg/L | 9 µg/L | Not Detected |
| NEtFOSAA | 3/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 11Cl-PF3OUdS | 3/7/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTA | 3/7/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFUnA | 3/7/2023 | <0.002 µg/L | 0.002 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.