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Tap water quality report

Tumon, GU

EPA monitoring detected 12 contaminants across the 1 water supplier serving Tumon. A detection doesn't automatically mean the water is unsafe — see the highest level found for each below, with its EPA source and period.

1
water supplier
139,207
people served
12
contaminants found
GU rankings Lead in GU PFAS in GU

What was found in Tumon's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
6:2 Fts
0.1482 µg/L
No EPA limit set
 1/1 UCMR-5
PFOS
0.1350 µg/L
No EPA limit set
 1/1 UCMR-5
PFHXS
0.0800 µg/L
No EPA limit set
 1/1 UCMR-5
Pfpea
0.0475 µg/L
No EPA limit set
 1/1 UCMR-5
Pfhxa
0.0371 µg/L
No EPA limit set
 1/1 UCMR-5
PFBS
0.0349 µg/L
No EPA limit set
 1/1 UCMR-5
Pfhpa
0.0185 µg/L
No EPA limit set
 1/1 UCMR-5
PFOA
0.0183 µg/L
No EPA limit set
 1/1 UCMR-5
Pfba
0.0181 µg/L
No EPA limit set
 1/1 UCMR-5
Lead
0.0137 mg/L 91%
of the EPA limit 0.0150 mg/L
 1/1 LCR
Pfpes
0.0099 µg/L
No EPA limit set
 1/1 UCMR-5
8:2 Fts
0.0075 µg/L
No EPA limit set
 1/1 UCMR-5
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. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Tumon

SupplierPopulation served
GWA NORTHERN WATER SYSTEM 139,207

Frequently asked questions about Tumon tap water

Is Tumon tap water safe to drink?

EPA testing detected 12 contaminants in the water serving Tumon. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Tumon?

1 public water supplier report drinking-water monitoring for Tumon, GU to the EPA. Each is listed above with its population served.

What contaminants are in Tumon's water?

The contaminants EPA monitoring detected in Tumon include 6:2 Fts, PFOS, PFHXS, Pfpea, Pfhxa. The full list, with the highest level found and the data source, is in the table above.

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.