Mashantucket Pequot Water System
PWS ID: 010106001 · MASHANTUCKET, 01 06339-3060
PFAS Detected
6 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
26,445
Total Violations
172
Health-Based Violations
63
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- Native American
- Connections
- 154
- School/Daycare
- No
- MCL Violations
- 63
- Monitoring Violations
- 106
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 57 | 1993 |
| TTHM | MCL | 6 | 2018 |
| Coliform (TCR) | MR | 6 | 1993 |
| TTHM | MR | 6 | 2018 |
| Lead and Copper Rule | MR | 6 | 1993 |
| BHC-GAMMA | MR | 4 | 2016 |
| Endrin | MR | 3 | 2016 |
| Diquat | MR | 3 | 2016 |
| Endothall | MR | 3 | 2016 |
| OXAMYL | MR | 3 | 2016 |
| Simazine | MR | 3 | 2016 |
| Picloram | MR | 3 | 2016 |
| Dinoseb | MR | 3 | 2016 |
| Carbofuran | MR | 3 | 2016 |
| Atrazine | MR | 3 | 2016 |
| LASSO | MR | 3 | 2016 |
| Heptachlor | MR | 3 | 2016 |
| 2,4-D | MR | 3 | 2016 |
| 2,4,5-TP | MR | 3 | 2016 |
| HEXACHLOROBENZENE | MR | 3 | 2016 |
| Benzo(a)pyrene | MR | 3 | 2016 |
| Total Polychlorinated Biphenyls (PCB) | MR | 3 | 2016 |
| 1,2-DIBROMO-3-CHLOROPROPANE | MR | 3 | 2016 |
| ETHYLENE DIBROMIDE | MR | 3 | 2016 |
| Dalapon | MR | 3 | 2016 |
| Di(2-ethylhexyl) adipate | MR | 3 | 2016 |
| Toxaphene | MR | 3 | 2016 |
| Di(2-ethylhexyl) phthalate | MR | 3 | 2016 |
| Hexachlorocyclopentadiene | MR | 3 | 2016 |
| Pentachlorophenol | MR | 3 | 2016 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 19 of 120 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| 8:2 FTS | 9/27/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpA | 9/27/2023 | 0.0035 µg/L | 0.003 µg/L | Detected |
| PFHxS | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFNA | 9/27/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 9/27/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 9/27/2023 | 0.0074 µg/L | 0.004 µg/L | Detected |
| PFDA | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 9/27/2023 | 0.0092 µg/L | 0.003 µg/L | Detected |
| 11Cl-PF3OUdS | 9/27/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 9Cl-PF3ONS | 9/27/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 9/27/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 9/27/2023 | 0.0063 µg/L | 0.005 µg/L | Detected |
| PFBS | 9/27/2023 | 0.0036 µg/L | 0.003 µg/L | Detected |
| 4:2 FTS | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 9/27/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeA | 9/27/2023 | 0.0182 µg/L | 0.003 µg/L | Detected |
| PFMBA | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 9/27/2023 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFPeS | 9/27/2023 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 9/27/2023 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 9/27/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 9/27/2023 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFTA | 8/9/2023 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFTrDA | 8/9/2023 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NEtFOSAA | 8/9/2023 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NMeFOSAA | 8/9/2023 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| lithium | 8/9/2023 | <9 µg/L | 9 µg/L | Not Detected |
| PFMBA | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 5/13/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 5/13/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 5/13/2024 | 0.0034 µg/L | 0.003 µg/L | Detected |
| PFHxA | 5/13/2024 | 0.0097 µg/L | 0.003 µg/L | Detected |
| PFPeS | 5/13/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFEESA | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 5/13/2024 | 0.0191 µg/L | 0.003 µg/L | Detected |
| 6:2 FTS | 5/13/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 5/13/2024 | 0.0065 µg/L | 0.005 µg/L | Detected |
| HFPO-DA | 5/13/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFDA | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 5/13/2024 | 0.0033 µg/L | 0.003 µg/L | Detected |
| 9Cl-PF3ONS | 5/13/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| ADONA | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpS | 5/13/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 11Cl-PF3OUdS | 5/13/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 5/13/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFDoA | 5/13/2024 | <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.