Is Atascadero, CA tap water safe?
The short answer
1 of the 3 utilities serving Atascadero has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Atascadero State Hospital.
Atascadero Mutual Water Co, which serves the most people here, has 2 results above EPA’s new limit, which takes effect in 2029, 2 results above the health goal and 1 result above EPA’s health benchmark. The worst: PFOS at 22.3 ppt, above EPA’s new limit, which takes effect in 2029.
The water from Atascadero Mutual Water Co is very hard, typically 310 mg/L (18.1 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 Atascadero’s ZIP codes, from EPA’s estimates.
- Open report
Atascadero Mutual Water Co
California · serves 33,307 people · about 12,100 in Atascadero
2 results above EPA’s new limit, which takes effect in 2029, 2 results above the health goal and 1 result above EPA’s health benchmark. The worst: PFOS at 22.3 ppt, above EPA’s new limit, which takes effect in 2029. Hardness: very hard, typically 310 mg/L (18.1 grains per gallon).
No health-based violations since 2016
- Open report
Garden Farms C.W.D.
California · serves 440 people · about 170 in Atascadero
1 result above the health goal. The worst: Arsenic at 1.7 ppb, above the health goal. Hardness: very hard, typically 340 mg/L (19.9 grains per gallon).
No health-based violations since 2016
- Open report
Atascadero State Hospital
California · serves 1,100 people · under 100 in Atascadero
1 result above the action level, 2 results above EPA’s new limit, which takes effect in 2029 and 3 results above the health goal. The worst: Copper at 1.6 ppm, above the action level. Hardness: very hard, typically 435 mg/L (25.5 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 Atascadero Mutual Water Co’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 Atascadero
The 3 labs California certifies closest to Atascadero, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
County of San Luis Obispo Public Health Laboratory
San Luis Obispo, CA · about 13 miles
Certified for bacteria
Fruit Growers Laboratory, Inc.
San Luis Obispo, CA · about 15 miles
Certified for bacteria
Abalone Coast Analytical, Inc.
San Luis Obispo, CA · about 15 miles
Certified for bacteria
ZIP codes in Atascadero
Which ZIP codes are in Atascadero: 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 Atascadero
Other towns in San Luis Obispo County with a page of their own.
What to do next
- Read Atascadero Mutual Water Co’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