State drinking water records
Guam drinking water systems
5 community water systems serve Guam and are listed below under 1 county and on the pages of 54 cities and towns. Their own population figures add up to 186,886 people, a sum that counts people twice where one system sells water to another.
3 of them had at least one health-based violation in the last 10 years. None of those systems has one still unresolved.
2 rely mainly on groundwater and 3 on surface water, counting water bought from other systems.
Their lead service line inventories list 0 lead lines, 0 galvanized lines that must be replaced and 43,610 lines of unknown material.
2 systems have no service area map from EPA and are placed by mailing address.
- Community water systems
- 5
- People served, sum of each system's own figure
- 186,886
- Systems with a health-based violation, last 10 years
- 3
- Systems with one unresolved
- 0
- Lead service lines in inventories
- 0
Counties
1 countyEach county counts the systems whose service area map reaches it. Systems placed only by a mailing address are listed on the county pages but not counted here.
| County | Systems | People served | With a health-based violation, 10 years | With one unresolved |
|---|---|---|---|---|
| Guam | 3 | 166,406 | 2 | 0 |
Largest systems
| System | Main county | People served | Main source | Health-based violations, 10 years | Unresolved | Lead lines |
|---|---|---|---|---|---|---|
| Gwa Northern Water System | Guam | 139,207 | Groundwater | 0 | 0 | 0 |
| Gwa Central Water System | Guam | 21,398 | Purchased surface water | 1 | 0 | 0 |
| U.S. Navy Water System | Guam | 12,780 | Surface water | 2 | 0 | 0 |
| Andersen Air Force Base Water System | Guam | 7,700 | Groundwater | 0 | 0 | 0 |
| Gwa Southern Water System | Guam | 5,801 | Surface water | 1 | 0 | 0 |
Counties come from the counties EPA lists each system serving, matched to 2024 Census counties; where EPA lists none, from the county coded in the system's ID, its service area map, or its mailing address. A county holding at least a fifth of a system's service area map is added when at least a fifth of that map lies in those counties. Towns are the ones EPA lists and the Census places such a map covers, always inside those counties. In New England, where EPA's town names a whole Town, it is not matched to the village of the same name. A system is not listed in a county holding less than a fifth of its map, or in a county or town its map reaches when the map lies mostly outside the counties EPA lists, so a page can leave out a system that serves part of the area. Methodology and limitations