Is Graton, CA tap water safe?
The short answer
None of the 3 utilities serving Graton has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records.
City of Sebastopol, which serves the most people here, has 1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 16.3 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
The water from City of Sebastopol is moderately hard to hard depending on the source, 101 to 160 mg/L (5.9 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 Graton’s ZIP codes, from EPA’s estimates.
- Open report
City of Sebastopol
California · serves 7,522 people · about 150 in Graton
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 16.3 ppb, above EPA’s health benchmark. Hardness: moderately hard to hard depending on the source, 101 to 160 mg/L (5.9 to 9.4 grains per gallon).
No health-based violations since 2016
- Open report
Graton Mutual Water System
California · serves 50 people · nearly all in Graton
Nothing in its records is above a health goal. Hardness: moderately hard, 92 mg/L (5.4 grains per gallon).
No health-based violations since 2016
- Open report
Downtown Graton Mutual Water System
California · serves 44 people · nearly all in Graton
Nothing in its records is above a health goal. Hardness: very hard, typically 215 mg/L (12.6 grains per gallon).
No health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in City of Sebastopol’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Water testing near Graton
The 3 labs California certifies closest to Graton, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
K Prime, LLC.
Santa Rosa, CA · about 7 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, PFAS
Brelje and Race Laboratories, Inc.
Santa Rosa, CA · about 9 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts
Sonoma County Public Health Laboratory
Santa Rosa, CA · about 9 miles
Certified for bacteria
Which ZIP codes are in Graton: 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 Graton
Other towns in Sonoma County with a page of their own.
What to do next
- Read City of Sebastopol’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water