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Is Asan, GU tap water safe?

2 utilities serve Asan, by EPA’s records. Here is what EPA’s records show for each, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

1 of the 2 utilities serving Asan has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s records: Gwa Central Water System.

Gwa Northern Water System, which serves the most people here, has 3 results above EPA’s new limit, which takes effect in 2029 and 1 result above the health goal. The worst: PFOS at 135 ppt, above EPA’s new limit, which takes effect in 2029.

A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in Gwa Northern Water System’s water, which serves the most people here. Another utility’s report names what handles its own results.

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Every claim, and more filters, in the full report

Water testing near Asan

A utility tests the water it sends out. A test of your own tap shows what your pipes add, and on a private well it is the only test there is. It takes a lab Guam certifies.

TapBuff hasn’t read Guam’s list of certified labs yet. The national page links every state’s own list.

Certified labs, state by state

ZIP codes in Asan

Which ZIP codes are in Asan: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology.

Near Asan

Other towns in Guam with a page of their own.

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