Cloverdale Mutual Water Co.
What EPA’s and California’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.
- Serves
- 455 people
- Connections
- 147
- Water source
- Groundwater
- Based in
- Oxnard, CA
- County
- Ventura
- Owner
- Private
- Hardness
- Very hard
The ZIP code it serves
The short answer
1 result is above the health goal. The worst: Uranium, above the health goal. No health-based violations on file since 2016.
What handles itWhat was found
Uranium, nitrate, total trihalomethanes (TTHM), chromium (total), fluoride, haloacetic acids (HAA5) and arsenic: California’s own results, samples taken from Jan. 10, 2020 to June 22, 2026, with EPA’s 2012 to 2019 file for earlier years.
Above the health goal1
Uranium
Comes from the source
7.7ppb
Highest yearly average, 2021 to 2022
Averaged by year, the highest was 7.7 ppb, in 2022: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 8.4 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15 ppb, in 2019.
What handles it
- NSF/ANSI 58 look for “Uranium”
Below EPA’s limits5
Nitrate
Comes from the source
6.3ppm
Highest sample; found in 183 of 183
2026 average: 1.9 ppm
The highest sample, in 2020, was 6.3 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its 15 samples averaged 1.9 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 12.1 ppm, in 2019.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Total trihalomethanes (TTHM)
Forms or is added in treatment
27ppb
Highest yearly average, 2020 to 2026
2026: not found
Averaged by year, the highest was 27 ppb, in 2022, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 69 ppb, in 2019.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Chromium (total)
Comes from the source
28ppb
Highest yearly average, 2021 to 2025
Averaged by year, the highest was 28 ppb, in 2025, below EPA’s legal limit of 100 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.0 ppb, in 2015.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
Fluoride
Forms or is added in treatment
0.7ppm
Highest yearly average, 2021 to 2025
2025 average: 0.7 ppm
Averaged by year, the highest was 0.7 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its two samples averaged 0.7 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.7 ppm, in 2015.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Haloacetic acids (HAA5)
Forms or is added in treatment
8.0ppb
Highest yearly average, 2020 to 2025
2025: not found
Averaged by year, the highest was 8.0 ppb, in 2022, below EPA’s legal limit of 60 ppb. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15 ppb, in 2019.
What handles it
No certification claim covers this compound yet.
2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Arsenic
- Lead
What handles it
A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”
- NSF/ANSI 58
Claim: Uranium
For: Uranium
At the tap, or for the whole house?
These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. How whole-house systems compare.
Filters with those claims on a certifier’s listing
None of the filters TapBuff has checked so far carry these claims. Search the certifier listings for the claim above.
Compare five-year costsHardness
Very hard, typically 531 mg/L (31.1 grains per gallon), across 3 sampling points, 2019 to 2025.
Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.
Violations since 2016
No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.
What this report can’t tell you
Everything else. Uranium, nitrate, total trihalomethanes (TTHM), chromium (total), fluoride, haloacetic acids (HAA5) and arsenic results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Cloverdale Mutual Water Co.’s own annual report, which it must send you every year, has the contaminants this page does not show.
Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.
What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.
Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; California’s results run from Jan. 10, 2020 to June 22, 2026.
Testing your own tap
The 3 labs California certifies closest to the area Cloverdale Mutual Water Co. serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Ventura County Public Health Laboratory
Oxnard, CA · about 3 miles
Certified for bacteria
Capco Analytical Services
Ventura, CA · about 3 miles
Certified for bacteria, nitrate, metals, minerals and other inorganics
Fruit Growers Laboratory, Inc.
Santa Paula, CA · about 9 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- California State Water Resources Control Board, Division of Drinking Water, results from Jan. 1, 2020 to July 17, 2026, read Oct. 8, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation, read Oct. 17, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Hardness: California State Water Resources Control Board, Division of Drinking Water, results from March 8, 2019 to July 24, 2025, read Oct. 10, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID CA5610068. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on UraniumWhat each one does to health, where it comes from, and the certification claim that addresses it.About Uranium
- Get the utility’s own reportCloverdale Mutual Water Co. must send you a water quality report every year. It covers contaminants this page does not show.How to read it
- Test your own tap for leadYour service line, solder and fixtures decide the lead at your faucet, not the utility’s average.Lead in your water: what to do
- Compare certified filtersWhat the filters certified for these results cost over five years, cartridges included.Compare five-year costs