Results from entry points (water leaving treatment, not household taps) of public water systems sampled under EPA's Fifth Unregulated Contaminant Monitoring Rule. Click a county to see every water system serving it, or turn on service areas and click a location to see the systems that serve that spot.
5 of the 8 public water systems listed for Guam were sampled. Sorted by the highest single result relative to EPA's 2024 limits. Each name links to a page with all of that system's results. All 8 Guam systems, including those not tested · Download all Guam results (CSV, gzip)
| System | PWSID | City | Population | PFOA (ppt) | PFOS (ppt) | HI | Highest single result |
|---|---|---|---|---|---|---|---|
| Gwa Northern Water System | GU0000006 | Mangilao | 139,207 | 18.3 | 135 | 8.005 | PFOS ≥ 3 × its limit |
| Andersen Air Force Base Water System | GU0000009 | Apo Ap | 7,700 | <MRL | <MRL | 0.34 | Hazard Index below its limit |
| U.S. Navy Water System | GU0000010 | Fpo Ap | 12,780 | <MRL | <MRL | 0.34 | Hazard Index below its limit |
| Gwa Central Water System | GU0000003 | Mangilao | 8,828 | <MRL | <MRL | 0 | No PFAS detected |
| Gwa Southern Water System | GU0000001 | Mangilao | 5,801 | <MRL | <MRL | 0 | No PFAS detected |
Highest single result for each system; PFOA and PFOS in ppt (ng/L). Entry-point samples, not tap water; screening comparisons, not compliance determinations.