Is McSwain, CA tap water safe?
The short answer
Neither of the 2 utilities serving McSwain 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 Atwater, which serves the most people here, has 3 results above EPA’s new limit, which takes effect in 2029 and 3 results above the health goal. The worst: PFOS at 45 ppt, above EPA’s new limit, which takes effect in 2029.
The water from City of Atwater is soft to hard depending on the source, 30 to 150 mg/L (1.8 to 8.8 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 McSwain’s ZIP codes, from EPA’s estimates.
- Open report
City of Atwater
California · serves 29,479 people · about 2,100 in McSwain
3 results above EPA’s new limit, which takes effect in 2029 and 3 results above the health goal. The worst: PFOS at 45 ppt, above EPA’s new limit, which takes effect in 2029. Hardness: soft to hard depending on the source, 30 to 150 mg/L (1.8 to 8.8 grains per gallon).
No health-based violations since 2016
- Open report
City of Merced
California · serves 96,073 people · about 140 in McSwain
3 results above EPA’s new limit, which takes effect in 2029 and 2 results above the health goal. The worst: PFOS at 8.9 ppt, above EPA’s new limit, which takes effect in 2029. Hardness: soft to very hard depending on the source, 59 to 260 mg/L (3.5 to 15.2 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 Atwater’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, Nitrate, 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, Nitrate, Arsenic
Culligan 10-Cup Pitcher with ZeroWater Technology (ZEROP10)
Pitcher
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 9, 2026
Certified for: PFOS, PFOA, PFHxS, Nitrate
Water testing near McSwain
The 3 labs California certifies closest to McSwain, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Microbac Laboratories, Inc. - Turlock
Turlock, CA · about 22 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity
Certified Laboratories - Turlock
Turlock, CA · about 22 miles
Certified for bacteria
Aemtek, Inc.
Modesto, CA · about 37 miles
Certified for bacteria
Which ZIP codes are in McSwain: 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 McSwain
Other towns in Merced County with a page of their own.
What to do next
- Read City of Atwater’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