Is Twain, CA tap water safe?
The short answer
2 of the 2 utilities serving Twain have a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Frccsd Old Mill Ranch and Frccsd Hot Springs.
Frccsd Old Mill Ranch, which serves the most people here, has 2 results above the health goal. The worst: Arsenic at 4.5 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.
The water from Frccsd Old Mill Ranch is hard, 161 mg/L (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 Twain’s ZIP codes, from EPA’s estimates.
- Open report
Frccsd Old Mill Ranch
California · serves 32 people · under 100 in Twain
2 results above the health goal. The worst: Arsenic at 4.5 ppb, above the health goal. Hardness: hard, 161 mg/L (9.4 grains per gallon).
1 health-based violation since 2016
- Open report
Frccsd Hot Springs
California · serves 25 people · under 100 in Twain
1 result above the health goal. The worst: Lead at 0.56 ppb, above the health goal. Hardness: soft, 35 mg/L (2 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 Frccsd Old Mill Ranch’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, Lead
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, Lead
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, Lead
Water testing near Twain
The 2 labs California certifies closest to Twain, 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 43 miles
Certified for bacteria
Cranmer Engineering, Inc.
Grass Valley, CA · about 56 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics
ZIP codes in Twain
Which ZIP codes are in Twain: 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 Twain
Other towns in Plumas County with a page of their own.
What to do next
- Read Frccsd Old Mill Ranch’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- Filters for ArsenicRanked by certification and what they cost over five years.The best reverse osmosis systems, ranked
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water