Is Cohasset, CA tap water safe?
The short answer
1 of the 3 utilities serving Cohasset has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Sierra Moon Mutual Water Company.
Cal - Water Service Co. - Chico, which serves the most people here, has 3 results above EPA’s new limit, which takes effect in 2029 and 2 results above the health goal. The worst: PFOS at 22.5 ppt, above EPA’s new limit, which takes effect in 2029.
The water from Cal - Water Service Co. - Chico is moderately hard to very hard depending on the source, 84 to 295 mg/L (4.9 to 17.3 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 Cohasset’s ZIP codes, from EPA’s estimates.
- Open report
Cal - Water Service Co. - Chico
California · serves 110,473 people · about 2,500 in Cohasset
3 results above EPA’s new limit, which takes effect in 2029 and 2 results above the health goal. The worst: PFOS at 22.5 ppt, above EPA’s new limit, which takes effect in 2029. Hardness: moderately hard to very hard depending on the source, 84 to 295 mg/L (4.9 to 17.3 grains per gallon).
No health-based violations since 2016
- Open report
Keefer Creek Estates
California · serves 160 people · under 100 in Cohasset
Nothing in its records is above a health goal. Hardness: moderately hard to hard depending on the source, 108 to 122 mg/L (6.3 to 7.1 grains per gallon).
No health-based violations since 2016
- Open report
Sierra Moon Mutual Water Company
California · serves 330 people · under 100 in Cohasset
1 result above the health goal. The worst: Arsenic at 2.0 ppb, above the health goal. Hardness: soft to moderately hard depending on the source, 21 to 104 mg/L (1.2 to 6.1 grains per gallon).
1 health-based violation since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in Cal - Water Service Co. - Chico’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: PFOS, PFOA, 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: PFOS, PFOA, 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: PFOS, PFOA, Arsenic
Water testing near Cohasset
The 3 labs California certifies closest to Cohasset, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Fruit Growers Laboratory, Inc.
Chico, CA · about 10 miles
Certified for bacteria
Pace Analytical Services, LLC - Redding
Redding, CA · about 56 miles
Certified for bacteria
Cranmer Engineering, Inc.
Grass Valley, CA · about 62 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics
ZIP codes in Cohasset
Which ZIP codes are in Cohasset: 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 Cohasset
Other towns in Butte County with a page of their own.
What to do next
- Read Cal - Water Service Co. - Chico’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- Filters for PFOSRanked by certification and what they cost over five years.The best water filters for PFAS, ranked
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water