CITY OF MERCEDES
PWS ID: TX1080007 · MERCEDES, Texas 78570-0837
PFAS Detected
2 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
16,258
Total Violations
112
Health-Based Violations
33
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 6,061
- County
- Hidalgo
- School/Daycare
- No
- MCL Violations
- 30
- Monitoring Violations
- 49
- Treatment Tech Violations
- 3
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MCL | 21 | 2013 |
| Public Notice | Other | 14 | 2025 |
| Coliform (TCR) | MCL | 9 | 2012 |
| E. COLI | MR | 7 | 2020 |
| Coliform (TCR) | MR | 6 | 2011 |
| Total Haloacetic Acids (HAA5) | MR | 4 | 2012 |
| TTHM | MR | 4 | 2012 |
| Interim Enhanced Surface Water Treatment Rule | MR | 3 | 2008 |
| LEAD AND COPPER RULE REVISIONS | TT | 2 | 2024 |
| LEAD AND COPPER RULE REVISIONS | RPT | 2 | 2024 |
| 1,2,4-Trichlorobenzene | MR | 1 | 2009 |
| Xylenes, Total | MR | 1 | 2009 |
| o-Dichlorobenzene | MR | 1 | 2009 |
| 1,2-Dichloroethane | MR | 1 | 2009 |
| 1,1,1-Trichloroethane | MR | 1 | 2009 |
| Carbon tetrachloride | MR | 1 | 2009 |
| Trichloroethylene | MR | 1 | 2009 |
| Tetrachloroethylene | MR | 1 | 2009 |
| Ethylbenzene | MR | 1 | 2009 |
| Styrene | MR | 1 | 2009 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 2006 |
| Lead and Copper Rule | MR | 1 | 2013 |
| cis-1,2-Dichloroethylene | MR | 1 | 2009 |
| Combined Radium (-226 and -228) | MR | 1 | 2006 |
| 1,1,2-Trichloroethane | MR | 1 | 2009 |
| p-Dichlorobenzene | MR | 1 | 2009 |
| 1,2-Dichloropropane | MR | 1 | 2009 |
| Vinyl chloride | MR | 1 | 2009 |
| Interim Enhanced Surface Water Treatment Rule | TT | 1 | 2012 |
| 1,1-Dichloroethylene | MR | 1 | 2009 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 5 of 120 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| 4:2 FTS | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTrDA | 7/24/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFDoA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTA | 7/24/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFPeS | 7/24/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NFDHA | 7/24/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFEESA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 7/24/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpS | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 7/24/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFBS | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxS | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 7/24/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| lithium | 7/24/2023 | 61.4000 µg/L | 9 µg/L | Detected |
| PFOS | 7/24/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFUnA | 7/24/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| NMeFOSAA | 7/24/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 6:2 FTS | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NEtFOSAA | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 11Cl-PF3OUdS | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 7/24/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 7/24/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 7/24/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 4/5/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 6:2 FTS | 4/5/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 4/5/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFMBA | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 4/5/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 4/5/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 4/5/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NFDHA | 4/5/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| NEtFOSAA | 4/5/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTA | 4/5/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFBS | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 4/5/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NMeFOSAA | 4/5/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| lithium | 4/5/2023 | 56.0000 µg/L | 9 µg/L | Detected |
| PFHxS | 4/5/2023 | <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.