Is Oakdale, CA tap water safe?
The short answer
1 of the 10 utilities serving Oakdale 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 Oakdale.
City of Oakdale, which serves the most people here, has 2 results above the health goal. The worst: Arsenic at 2.6 ppb, above the health goal. Health goals are stricter than legal limits and are not enforced.
The water from City of Oakdale is soft to hard depending on the source, 53 to 123 mg/L (3.1 to 7.2 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 Oakdale’s ZIP codes, from EPA’s estimates.
- Open report
City of Oakdale
California · serves 23,235 people · about 670 in Oakdale
2 results above the health goal. The worst: Arsenic at 2.6 ppb, above the health goal. Hardness: soft to hard depending on the source, 53 to 123 mg/L (3.1 to 7.2 grains per gallon).
1 health-based violation since 2016
- Open report
Oid - Oakdale Rural Water System #1
California · serves 1,570 people · under 100 in Oakdale
1 result above the health goal. The worst: Arsenic at 0.56 ppb, above the health goal. Hardness: soft to hard depending on the source, 57 to 173 mg/L (3.3 to 10.1 grains per gallon).
No health-based violations since 2016
- Open report
Oid #46 - Sunset Oaks
California · serves 269 people · under 100 in Oakdale
Nothing in its records is above a health goal. Hardness: soft to very hard depending on the source, 60 to 195 mg/L (3.5 to 11.4 grains per gallon).
No health-based violations since 2016
- Open report
North Oaks Mutual Water Co
California · serves 234 people · under 100 in Oakdale
1 result above the health goal. The worst: Arsenic at 2.5 ppb, above the health goal. Hardness: soft to moderately hard depending on the source, 58 to 91 mg/L (3.4 to 5.3 grains per gallon).
No health-based violations since 2016
- Open report
Oid #51 - Sunset Oaks #10
California · serves 287 people · under 100 in Oakdale
Nothing in its records is above a health goal. Hardness: moderately hard to hard depending on the source, 113 to 138 mg/L (6.6 to 8.1 grains per gallon).
No health-based violations since 2016
- Open report
Twin Cypress Mobile Home Park
California · serves 112 people · under 100 in Oakdale
1 result above the health goal. The worst: Arsenic at 7.0 ppb, above the health goal. Hardness: moderately hard, 78 mg/L (4.6 grains per gallon).
No health-based violations since 2016
- Open report
4n Mobilehome Park
California · serves 65 people · under 100 in Oakdale
2 results above the health goal. The worst: Lead at 4.2 ppb, above the health goal. Hardness: moderately hard, 110 mg/L (6.4 grains per gallon).
No health-based violations since 2016
- Open report
Oid #22 - Williams Tract
California · serves 150 people · under 100 in Oakdale
1 result above the health goal. The worst: Lead at 1.3 ppb, above the health goal. Hardness: moderately hard, 101 mg/L (5.9 grains per gallon).
No health-based violations since 2016
- Open report
Oid #45
California · serves 144 people · under 100 in Oakdale
1 result above the health goal. The worst: Arsenic at 2.8 ppb, above the health goal. Hardness: soft to very hard depending on the source, 60 to 189 mg/L (3.5 to 11 grains per gallon).
No health-based violations since 2016
- Open report
Lone Pine MHP
California · serves 64 people · under 100 in Oakdale
2 results above the health goal. The worst: Nitrate at 11 ppm, above the health goal. Hardness: moderately hard, typically 85 mg/L (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 City of Oakdale’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 Oakdale
The 3 labs California certifies closest to Oakdale, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Aemtek, Inc.
Modesto, CA · about 14 miles
Certified for bacteria
Institute of Environmental Health, Inc. dba IEH-JL Analytical
Modesto, CA · about 18 miles
Certified for bacteria, nitrate, minerals and other inorganics
Microbac Laboratories, Inc. - Turlock
Turlock, CA · about 21 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity
ZIP codes in Oakdale
Which ZIP codes are in Oakdale: 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 Oakdale
Other towns in Stanislaus County with a page of their own.
What to do next
- Read City of Oakdale’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