ESTERO MUNICIPAL IMPROVEMENT DISTRICT
PWS ID: CA4110021 · FOSTER CITY, California 94404
Population Served
36,556
Total Violations
7
Health-Based Violations
3
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 8,035
- County
- San Mateo
- School/Daycare
- No
- MCL Violations
- 2
- Monitoring Violations
- 3
- Treatment Tech Violations
- 1
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 2 | 2007 |
| TTHM | MR | 2 | 2022 |
| Lead and Copper Rule | MR | 1 | 1993 |
| Surface Water Treatment Rule | TT | 1 | 1992 |
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 | 6/22/2023 | <9 µg/L | 9 µg/L | Not Detected |
| NMeFOSAA | 6/22/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| NEtFOSAA | 6/22/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTA | 6/22/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFTrDA | 6/22/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFMBA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 4/13/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 8:2 FTS | 4/13/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFPeA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| ADONA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 4/13/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFEESA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 4/13/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 9Cl-PF3ONS | 4/13/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 4/13/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 4/13/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOS | 4/13/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 4/13/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 4/13/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 4/13/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| HFPO-DA | 4/13/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpS | 4/13/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 4/13/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| HFPO-DA | 3/28/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFDA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 3/28/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 3/28/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 3/28/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| ADONA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 3/28/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 3/28/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 3/28/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFTrDA | 3/28/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| 9Cl-PF3ONS | 3/28/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| lithium | 3/28/2023 | <9 µg/L | 9 µg/L | Not Detected |
| 8:2 FTS | 3/28/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOS | 3/28/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFEESA | 3/28/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 3/28/2023 | <0.006 µg/L | 0.006 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.