Adelup, GU · PWSID GU0000003
Gwa Central Water System lead service lines
2,658 lines still unidentified
Gwa Central Water System reported no confirmed lead service lines, but 2,658 of 2,919 lines (91%) are still listed as "lead status unknown." Until a line is identified, treat it as possibly lead.
0% of Gwa Central Water System's service lines are lead or galvanized requiring replacement. That's about the same as the Guam average (0%) and lower than the national average (3.1%).
- Lead 0%
- Galvanized (replace) 0%
- Unknown 91%
- Non-lead 8.9%
Total service lines reported: 2,919. Reported all required service line types. Population served: 8,828; 3,295 connections.
Lead test results
Gwa Central Water System's most recent 90th-percentile lead result (Jan 2023–Dec 2025) was 0.8 ppb, below both the 15 ppb action level and the 10 ppb level that takes effect in 2027. This means 90% of homes sampled were at or below that level; individual homes, especially those with lead lines, can be higher.
Lead and Copper Rule 90th-percentile results reported to EPA, in parts per billion. Dashed lines: 15 ppb action level and the 10 ppb level from November 1, 2027.
Progress since 2025 Q1
Reported lead and galvanized-requiring-replacement lines went from 0 in 2025 Q1 to 0 in 2026 Q3: no change. Lines of unknown material went from 2,658 to 2,658, no change.
Quarterly counts reported to EPA. A drop usually means lines were replaced or confirmed non-lead; a rise usually means more lines were identified. Replacement progress rankings.
Lead rule violations
EPA's data lists no Lead and Copper Rule violations for Gwa Central Water System since 2015. That covers testing, reporting, corrosion control and public notice requirements; it isn't a guarantee about any individual home.
Source: EPA SDWIS violation records for the Lead and Copper Rule.
Where the water comes from
Gwa Central Water System's main water source is purchased surface water. It buys treated water from U.S. Navy Water System. The seller treats the water, including corrosion control that keeps lead from dissolving out of pipes, while Gwa Central Water System is responsible for its own service line inventory and replacement program. It sells water to 1 other water system: U.S. Navy Water System.
Source: EPA SDWIS water system and facility records.
Check your own address
These counts cover the whole system. To see whether your line is lead, use the utility's address-level inventory. Utilities had to prepare one by October 16, 2024 and make it publicly accessible; systems serving more than 50,000 people must post it online.
No map yet? Do the 2-minute scratch and magnet test on the pipe where water enters your home.
Protect your drinking water now
If your line is lead, galvanized or unknown, filter water for drinking, cooking and baby formula. Use a filter certified to NSF/ANSI 53 for lead. Run cold water for a few minutes after it sits for hours, and never use hot tap water for cooking.
How to pick a lead-certified filter · How to test your water for lead
Getting the line replaced
EPA's Lead and Copper Rule Improvements require most systems to replace lead and galvanized-requiring-replacement lines by December 31, 2037. Ask Gwa Central Water System whether it replaces the private side for free or with a cost share before you hire anyone. If you want it done sooner, or your utility doesn't cover your side, a licensed plumber can quote it. What replacement costs.
County pages: Lead pipes in Guam County
ZIP codes served
ZIP codes whose center falls inside Gwa Central Water System's mapped service area (EPA service area boundaries). Neighboring utilities may serve parts of the same ZIP.
96928
Other water systems nearby
| System | Lead + galv. | Unknown |
|---|---|---|
| Gwa Northern Water System | 0 | 38,633 |
| U.S. Navy Water System | 0 | 0 |
| Andersen Air Force Base Water System | 0 | 0 |
| Gwa Southern Water System | 0 | 2,319 |
Check another water system
Questions
Does Gwa Central Water System have lead pipes?
It hasn't confirmed any, but 2,658 of its 2,919 service lines are still of unknown material, so lead has not been ruled out.
How do I check if my home's service line is lead?
Look up your address on Gwa Central Water System's official service line inventory, which utilities must make publicly available. You can also scratch the pipe where it enters your home: lead is soft, dull gray, scratches to shiny silver and does not attract a magnet.
When will Gwa Central Water System replace lead service lines?
Under EPA's Lead and Copper Rule Improvements, most systems must replace lead and galvanized-requiring-replacement lines by December 31, 2037, starting from November 1, 2027. The rule is being challenged in court, so dates could change. Many utilities run free or cost-share programs now.
Has Gwa Central Water System had lead violations?
EPA's data shows no Lead and Copper Rule violations since 2015 for Gwa Central Water System.
Which water filters remove lead?
Use a filter certified to NSF/ANSI Standard 53 for lead reduction, or NSF/ANSI 58 for reverse osmosis. Check the certification on NSF's listings, not just the box.
Embed or cite this data
Local news sites, blogs and community groups can embed this card. It updates when EPA releases new data.
Citation: Lead Pipe Map, "Gwa Central Water System lead service lines," https://leadpipemap.com/gu/gwa-central-water-system/. Source: EPA SDWIS service line inventory, 2026 Q3. Download the full dataset on the data page.