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Old River 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
130 people
Connections
19
Water source
Groundwater
Based in
Clovis, CA
County
Kern
Owner
Private
Hardness
Very hard
The ZIP code it serves

93311

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Uranium, above the legal limit. 17 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 1997 to 2026.

Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM): California’s own results, samples taken from March 10, 2020 to April 8, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Uranium

Comes from the source

Above the legal limit

42.1ppb

Highest yearly average, 2020 to 2026

2026 average: 33.5 ppb

Averaged by year, the highest was 42.1 ppb, in 2024, above EPA’s legal limit of 30 ppb. Its highest single sample was 50.7 ppb. In 2026, the latest year on file, its two samples averaged 33.5 ppb, above the limit. EPA recorded violations for uranium at this utility in 2024 and 2025. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 50.7 ppb, in 2012, and EPA recorded violations in 2013, 2014, 2015, 2016, 2017 and 2018.

What handles it

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

1.0ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 1.0 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Below EPA’s limits2

Nitrate

Comes from the source

Below EPA’s limits

6.4ppm

Highest sample; found in 10 of 10

2026, one sample: 4.5 ppm

The highest sample, in 2025, was 6.4 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 4.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 7.9 ppm, in 2013.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.059ppm

Highest yearly average, 2021 to 2024

Averaged by year, the highest was 0.059 ppm, in 2024, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Total trihalomethanes (TTHM)

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.”

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. 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 water filters for lead, ranked

Hardness

Very hard, 235 mg/L (13.7 grains per gallon), at its one sampling point, 2021 to 2024.

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 13.7 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2025 to Dec. 31, 202522 PCI/LResolved
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2025 to Sept. 30, 202522 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2025 to June 30, 202524 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2025 to March 31, 202527 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2024 to Dec. 31, 202428 PCI/LArchived
Revised Total Coliform RuleE. coli was confirmed in the water system.EPA: Maximum Contaminant Level Violation, E. coli (RTCR)July 1, 2024 to July 31, 2024—Resolved
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2018 to Sept. 30, 201827 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2018 to June 30, 201828 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2018 to March 31, 201827 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2017 to Dec. 31, 201728 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2017 to Sept. 30, 201727 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 201729 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2017 to March 31, 201729 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2016 to Dec. 31, 201629 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2016 to Sept. 30, 201628.5 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2016 to June 30, 201628 PCI/LArchived
Combined UraniumThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2016 to March 31, 201626.8 PCI/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. Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Old River 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 March 10, 2020 to April 8, 2026.

Testing your own tap

Old River 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 Old River Mutual Water Company serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • BSK Associates - Bakersfield Analytical Laboratory

    Bakersfield, CA · about 15 miles

    Certified for bacteria

    (661) 327-0671

  • Zalco Laboratories, Inc.

    Bakersfield, CA · about 16 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 16 miles

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

    (661) 327-4911

All 145 certified labs for California

Sources

PWSID CA1500096. Rebuilt from EPA data on Oct. 18, 2026.

Also in Kern County

All California utilities

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