Skip to content
TapBuff
ZIP

Is Sonoma, CA tap water safe?

6 utilities serve Sonoma, 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

1 of the 6 utilities serving Sonoma has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Diamond A Mutual Water Company.

Valley of the Moon Water District, which serves the most people here, has 2 results above EPA’s new limit, which takes effect in 2029, 1 result above the health goal and 1 result above EPA’s health benchmark. The worst: PFOS at 5.4 ppt, above EPA’s new limit, which takes effect in 2029.

The water from Valley of the Moon Water District is soft to hard depending on the source, 42 to 160 mg/L (2.5 to 9.4 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 Sonoma’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 Valley of the Moon Water District’s water, which serves the most people here. Another utility’s report names what handles its own results.

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Every claim, and more filters, in the full report

Water testing near Sonoma

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

  • Alpha Analytical Laboratories Inc. - North Bay

    Petaluma, CA · about 10 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, PFAS

    (707) 769-3128

  • Caltest Analytical Laboratory

    Napa, CA · about 11 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts

    (707) 258-4000

  • Brelje and Race Laboratories, Inc.

    Santa Rosa, CA · about 18 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts

    (707) 544-8807

All 145 certified labs for California

ZIP codes in Sonoma

Which ZIP codes are in Sonoma: 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 Sonoma

Other towns in Sonoma County with a page of their own.

What to do next