TWIN FALLS CITY OF
PWS ID: ID5420058 · TWIN FALLS, Idaho 83301
PFAS Detected
1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
Population Served
56,121
Total Violations
164
Health-Based Violations
120
Water Source
Groundwater
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 19,273
- County
- Twin Falls
- School/Daycare
- No
- MCL Violations
- 120
- Monitoring Violations
- 27
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 117 | 2012 |
| Public Notice | Other | 10 | 2012 |
| Nitrate | MR | 7 | 2023 |
| E. COLI | MR | 6 | 2015 |
| Lead and Copper Rule | MR | 6 | 2022 |
| Coliform (TCR) | MCL | 3 | 2007 |
| Chlorine | MR | 2 | 2005 |
| Coliform (TCR) | MR | 2 | 1997 |
| Nitrite | MR | 2 | 2014 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2005 |
| TTHM | MR | 1 | 2005 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 3 of 65 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| NMeFOSAA | 5/20/2025 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFTA | 5/20/2025 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFTrDA | 5/20/2025 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NEtFOSAA | 5/20/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| lithium | 5/20/2025 | 40.8000 µg/L | 9 µg/L | Detected |
| HFPO-DA | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOS | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 11/20/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| ADONA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBA | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHpA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFBS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 11/20/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFTA | 11/20/2024 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFNA | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 11/20/2024 | 47.7000 µg/L | 9 µg/L | Detected |
| PFTrDA | 11/20/2024 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| NEtFOSAA | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NMeFOSAA | 11/20/2024 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| 6:2 FTS | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFEESA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 11/20/2024 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| 8:2 FTS | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFPeS | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFPeS | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| 8:2 FTS | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| HFPO-DA | 11/20/2024 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFOA | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| ADONA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 11/20/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFBS | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 11/20/2024 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFUnA | 11/20/2024 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFMPA | 11/20/2024 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDoA | 11/20/2024 | <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.