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Is South San Francisco, CA tap water safe?

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

Matched to your utility using EPA records.

The short answer

Neither of the 2 utilities serving South San Francisco has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records.

California Water Service - S San Francisco, which serves the most people here, has 3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 23.6 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.

The water from California Water Service - S San Francisco is very hard, typically 382 mg/L (22.3 grains per gallon). How California’s water compares.

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. They are listed by how many people each serves in South San Francisco’s ZIP codes, from EPA’s estimates.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in California Water Service - S San Francisco’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 South San Francisco

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 South San Francisco, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Garratt-Callahan Laboratory

    Burlingame, CA · about 5 miles

    Certified for nitrate, metals, minerals and other inorganics

    (650) 697-5811

  • Eurofins Built Environment Testing West-Burlingame

    Burlingame, CA · about 6 miles

    Certified for bacteria

    (623) 298-1015

  • Cel Analytical, Inc.

    San Francisco, CA · about 9 miles

    Certified for bacteria, minerals and other inorganics

    (415) 882-1690

All 145 certified labs for California

ZIP codes in South San Francisco

Which ZIP codes are in South San Francisco: 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 South San Francisco

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

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