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Is Atherton, CA tap water safe?

California Water Service - Bear Gulch serves Atherton, by EPA’s records. Here is what EPA’s and California’s records show for it, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

California Water Service - Bear Gulch serves Atherton. In EPA’s and California’s records it has 2 results above the health goal, and no health-based violation since 2016.

The worst: Lead at 4.0 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.

The water from California Water Service - Bear Gulch is moderately hard to very hard depending on the source, 65 to 281 mg/L (3.8 to 16.4 grains per gallon). How California’s water compares.

Some homes in a town are on private wells or a small system of their own. The name on your water bill tells you which is yours.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in California Water Service - Bear Gulch’s water.

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Every claim, and more filters, in the full report

Water testing near Atherton

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 California certifies.

The 3 labs California certifies closest to Atherton, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • San Mateo County Public Health Laboratory

    San Mateo, CA · about 8 miles

    Certified for bacteria

    (650) 573-2500

  • Eurofins Built Environment Testing West-Burlingame

    Burlingame, CA · about 12 miles

    Certified for bacteria

    (623) 298-1015

  • SGS North America

    Hayward, CA · about 13 miles

    Certified for bacteria

    (510) 266-8183

All 145 certified labs for California

ZIP codes in Atherton

Which ZIP codes are in Atherton: 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. Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation; distances from the Census 2020 ZIP code tabulation area gazetteer.

Near Atherton

Other towns in San Mateo County with a page of their own.

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