GWA CENTRAL WATER SYSTEM
PWS ID: GU0000003 · MANGILAO, Guam 96913
Population Served
21,398
Total Violations
106
Health-Based Violations
63
Water Source
Surface Water
System Details
- System Type
- Community
- Owner Type
- State
- Connections
- 3,295
- County
- Guam
- School/Daycare
- No
- MCL Violations
- 63
- Monitoring Violations
- 31
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| TTHM | MCL | 34 | 2012 |
| Total Haloacetic Acids (HAA5) | MCL | 19 | 2012 |
| Public Notice | Other | 8 | 2012 |
| Coliform (TCR) | MCL | 6 | 2011 |
| Revised Total Coliform Rule | MCL | 4 | 2022 |
| Barium | MR | 3 | 2012 |
| Cadmium | MR | 3 | 2012 |
| CYANIDE | MR | 3 | 2012 |
| Mercury | MR | 3 | 2012 |
| Antimony, Total | MR | 3 | 2012 |
| Selenium | MR | 3 | 2012 |
| Beryllium, Total | MR | 3 | 2012 |
| Thallium, Total | MR | 3 | 2012 |
| Chromium | MR | 3 | 2012 |
| Arsenic | MR | 3 | 2012 |
| Lead and Copper Rule | MR | 1 | 1992 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 180 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| PFMBA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 11Cl-PF3OUdS | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFUnA | 8/5/2025 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFHxA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDoA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFDA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFOA | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOS | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFNA | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHxS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 9Cl-PF3ONS | 8/5/2025 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| PFBS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 8/5/2025 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFHpA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| ADONA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| HFPO-DA | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBA | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 6:2 FTS | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| 4:2 FTS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 8:2 FTS | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFEESA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeS | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFHpS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| lithium | 8/5/2025 | <9 µg/L | 9 µg/L | Not Detected |
| NMeFOSAA | 8/5/2025 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| NEtFOSAA | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFTrDA | 8/5/2025 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 8/5/2025 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFPeA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| NMeFOSAA | 8/5/2025 | <0.006 µg/L | 0.006 µg/L | Not Detected |
| PFDoA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHxA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| 6:2 FTS | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| NEtFOSAA | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFBS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFTrDA | 8/5/2025 | <0.007 µg/L | 0.007 µg/L | Not Detected |
| PFTA | 8/5/2025 | <0.008 µg/L | 0.008 µg/L | Not Detected |
| PFEESA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMBA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFPeA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFMPA | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFUnA | 8/5/2025 | <0.002 µg/L | 0.002 µg/L | Not Detected |
| 11Cl-PF3OUdS | 8/5/2025 | <0.005 µg/L | 0.005 µg/L | Not Detected |
| PFHxS | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| PFHpA | 8/5/2025 | <0.003 µg/L | 0.003 µg/L | Not Detected |
| NFDHA | 8/5/2025 | <0.02 µg/L | 0.02 µg/L | Not Detected |
| PFOS | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFOA | 8/5/2025 | <0.004 µg/L | 0.004 µg/L | Not Detected |
| PFDA | 8/5/2025 | <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.