TOWN OF HILLSBOROUGH
PWS ID: CA4110016 · HILLSBOROUGH, California 94010
Population Served
11,766
Total Violations
5
Health-Based Violations
2
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 4,303
- County
- San Mateo
- School/Daycare
- No
- MCL Violations
- 2
- Monitoring Violations
- 2
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 2 | 1992 |
| Coliform (TCR) | MCL | 2 | 2014 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 120 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| lithium | 8/14/2024 | <9 µg/L | 9 µg/L | Not Detected |
| PFNA | 8/14/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 8/14/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 8/14/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDoA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 8/14/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxS | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 8/14/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFDA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| ADONA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 8/14/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 8/14/2024 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 11Cl-PF3OUdS | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 8:2 FTS | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 4:2 FTS | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 8/14/2024 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 6:2 FTS | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFMBA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTA | 8/14/2024 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFBS | 8/14/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTrDA | 8/14/2024 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NEtFOSAA | 8/14/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFMPA | 8/14/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFBA | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NEtFOSAA | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxA | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTA | 6/19/2024 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFHpS | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 6/19/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 6/19/2024 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 6/19/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 6:2 FTS | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NMeFOSAA | 6/19/2024 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| HFPO-DA | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 6/19/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 6/19/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 6/19/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 6/19/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFDoA | 6/19/2024 | <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.