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Wini Mutual Water Company

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
29 people
Connections
12
Water source
Groundwater
Based in
Bakersfield, CA
County
Kern
Owner
Private
Hardness
Very hard
The ZIP code it serves

93307

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Nitrate, above the legal limit. 9 health-based violations since 2016.

What handles it

What was found

Nitrate, arsenic, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5): California’s own results, samples taken from Feb. 5, 2020 to April 13, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

12ppm

Highest sample; found in 27 of 27

2026 average: 10.7 ppm

From 2020 to 2026, nine samples were above EPA’s legal limit of 10 ppm, the highest 12 ppm in 2021. The next sample at the same point, within 30 days, kept the average above the limit for one; eight have no follow-up sample on file within 30 days. In 2026, the latest year on file, its three samples averaged 10.7 ppm, above the limit. EPA recorded violations for nitrate at this utility in 2020, 2021, 2022 and 2023. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 24 ppm, in 2019, and EPA recorded a violation in 2019.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Above the health goal1

Arsenic

Comes from the source

Above the health goal

5.4ppb

Highest yearly average, 2020 to 2024

2024, one sample: 4.5 ppb

Averaged by year, the highest was 5.4 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2024, the latest year on file, its one sample was 4.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 5.6 ppb, in 2014.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits2

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.18ppm

Highest yearly average, 2020 to 2023

2023, one sample: 0.17 ppm

Averaged by year, the highest was 0.18 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2023, the latest year on file, its one sample was 0.17 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.18 ppm, in 2014.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

1.6ppb

Highest yearly average, 2020 to 2023

Averaged by year, the highest was 1.6 ppb, in 2023, below EPA’s legal limit of 80 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 4.8 ppb, in 2017.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Haloacetic acids (HAA5)
  • 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 53

    Claims: Nitrate/Nitrite (30 ppm challenge), Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Arsenic

    Other certifiers’ wording: Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Arsenic

    Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

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

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best reverse osmosis systems, ranked

Hardness

Very hard, 325 mg/L (19 grains per gallon), at its one sampling point, 2020 to 2023.

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.

Softeners compared at 19 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2023 to June 30, 202311 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2023 to March 31, 202311 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2022 to Dec. 31, 202211 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2022 to June 30, 202211 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2021 to March 31, 202112 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJuly 1, 2020 to Sept. 30, 202011 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2019 to Dec. 31, 201911 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMarch 1, 2019 to March 31, 201924 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleFeb. 1, 2019 to Feb. 28, 201911 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 1 monitoring or reporting violation not shown.

What this report can’t tell you

  • Everything else. Nitrate, arsenic, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Wini Mutual Water Company’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 Feb. 5, 2020 to April 13, 2026.

Testing your own tap

Wini Mutual Water Company’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab California certifies.

The 3 labs California certifies closest to the area Wini Mutual Water Company serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Zalco Laboratories, Inc.

    Bakersfield, CA · about 12 miles

    Certified for bacteria, nitrate, metals, minerals and other inorganics, organic chemicals, disinfection byproducts

    (661) 395-0539

  • Pace Analytical Services, LLC dba BC Laboratories, Inc.

    Bakersfield, CA · about 13 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity

    (661) 327-4911

  • BSK Associates - Bakersfield Analytical Laboratory

    Bakersfield, CA · about 16 miles

    Certified for bacteria

    (661) 327-0671

All 145 certified labs for California

Sources

PWSID CA1503526. Rebuilt from EPA data on Oct. 18, 2026.

Also in Kern County

All California utilities

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