This is a system-level descriptive percentage. It is not a household exposure estimate, population prevalence, health-risk estimate, or compliance determination.
Check potentially relevant systems
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
System counts in Guam
Each count is the number of unique eligible systems meeting the named technical comparison.
| Comparison | Systems meeting comparison | Eligible-system denominator | Percent |
|---|---|---|---|
| PFOA | 1 | 3 | 33.3% |
| PFOS | 1 | 3 | 33.3% |
| PFHxS | 1 | 3 | 33.3% |
| PFNA | 0 | 3 | 0.0% |
| HFPO-DA | 0 | 3 | 0.0% |
| Hazard Index | 1 | 3 | 33.3% |
Eligible monitored community water systems
Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Any comparison |
|---|---|---|---|---|---|
| ANDERSEN AIR FORCE BASE WATER SYSTEM | GU0000009 | 7,700 | Ground water | 4 | None met |
| GWA NORTHERN WATER SYSTEM | GU0000006 | 139,207 | Ground water | 58 | Meets at least one |
| U.S. NAVY WATER SYSTEM | GU0000010 | 12,780 | Surface water | 6 | None met |
What these results mean
The denominator is active community water systems with complete UCMR 5 monitoring in this state or territory. The numerator is unique systems with at least one complete-set sampling location meeting an individual PFAS or qualifying Hazard Index technical comparison. Systems are never copied or counted once per ZIP. UCMR 5 results do not establish household service, individual exposure, health risk, or regulatory compliance. Private wells are excluded, and small systems were not comprehensively monitored.
Related links
PFAS Estimator system lookupNational state comparison tableFull methodology and limitationsEPA UCMR 5 Data Finder