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Tap water quality report

Gwa Northern Water

EPA monitoring tested this supplier for 31 contaminants and detected 12. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

31
contaminants tested
12
detected
139,207
people served
6
health-based violations
Water source
Ground water
Ownership
State government
Counties served
Guam

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

6
health-based violations
18
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Archived 1985-01-29 → 1985-02-28
MCL Health-based Archived 1985-01-29 → 1985-02-28
MCL Health-based Archived 1985-01-10 → 1985-02-09
MCL Health-based Archived 1985-01-10 → 1985-02-09
MCL Health-based Archived 1985-01-07 → 1985-02-06
MCL Health-based Archived 1985-01-07 → 1985-02-06
Other Monitoring Archived 1981-06-10 → 1981-07-09
Other Monitoring Archived 1981-05-10 → 1981-06-09
Other Monitoring Archived 1981-03-14 → 1981-04-13
Other Monitoring Archived 1981-02-10 → 1981-03-09

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
PFHXS 0.0800 µg/L 77/115 2024
Pfpea 0.0475 µg/L 63/115 2024
Pfhxa 0.0371 µg/L 56/115 2024
PFBS 0.0349 µg/L 41/115 2024
PFOS 0.1350 µg/L 37/115 2024
Pfhpa 0.0185 µg/L 22/115 2024
PFOA 0.0183 µg/L 9/115 2024
Pfba 0.0181 µg/L 8/115 2024
6:2 Fts 0.1482 µg/L 5/115 2024
Pfpes 0.0099 µg/L 4/115 2024
8:2 Fts 0.0075 µg/L 1/115 2024

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Lead
0.0137 mg/L 91%
of the EPA limit 0.0150 mg/L
9/9 LCR 2025
19 contaminants tested, none detected
11Cl-PF3OUdS4:2 Fts9Cl-PF3ONSAdonaHfpo-DaNetfosaaNfdhaNmefosaaPfdaPfdoaPfeesaPfhpsPfmbaPfmpaPFNAPftaPftrdaPfunaLithium

Utility contact

Contact
BORDALLO, MIGUEL
Phone
671-300-6845
Email
mcbordallo@guamwaterworks.org

Frequently asked questions about Gwa Northern Water

Is Gwa Northern Water tap water safe to drink?

EPA monitoring detected 12 contaminants in Gwa Northern Water's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Gwa Northern Water's water?

EPA monitoring detected PFHXS, Pfpea, Pfhxa, PFBS, PFOS, and others. The full list with the level and data source for each is above.

How many people does Gwa Northern Water serve?

Gwa Northern Water reports serving 139,207 people in GU, per its EPA record.

Has Gwa Northern Water had any water quality violations?

The EPA has 18 violations on file for Gwa Northern Water, of which 6 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.