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South Kaweah 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
384 people
Connections
142
Water source
Groundwater
Based in
Three Rivers, CA
County
Tulare
Owner
Private
Hardness
Very hard
The ZIP code it serves

93271

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Arsenic, above the legal limit. 13 health-based violations since 2016.

What handles it

What was found

Arsenic, nitrate, chromium (total), total trihalomethanes (TTHM), fluoride and haloacetic acids (HAA5): California’s own results, samples taken from Feb. 6, 2020 to May 21, 2026, with EPA’s 2012 to 2019 file for earlier years.

Uranium: EPA’s compliance monitoring file, samples taken from Feb. 6, 2012 to May 8, 2019. Newer results are in the utility’s annual water quality report.

Above the legal limit1

Arsenic

Comes from the source

Above the legal limit

11.3ppb

Highest yearly average, 2020 to 2026

2026 average: 9.5 ppb

Averaged by year, the highest was 11.3 ppb, in 2020, above EPA’s legal limit of 10 ppb. Its highest single sample was 20 ppb. In 2026, the latest year on file, its four samples averaged 9.5 ppb. EPA recorded violations for arsenic at this utility in 2022, 2023, 2024, 2025 and 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 16.3 ppb, in 2017, and EPA recorded violations in 2012, 2013 and 2014.

What handles it

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

Above the health goal1

Uranium

Comes from the source

Above the health goal

8.0ppb

Highest yearly average, 2012 to 2019

2019, one sample: 7.0 ppb

Averaged by year, the highest was 8.0 ppb, in 2012: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 8.5 ppb. In 2019, the latest year on file, its one sample was 7.0 ppb.

What handles it

Below EPA’s limits4

Nitrate

Comes from the source

Below EPA’s limits

5.4ppm

Highest sample; found in 11 of 12

2025 average: 3.4 ppm

The highest sample, in 2023, was 5.4 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, its three samples averaged 3.4 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 8.1 ppm, in 2017.

What handles it

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

Chromium (total)

Comes from the source

Below EPA’s limits

26ppb

Highest yearly average, 2022 to 2025

2025 average: 6.5 ppb

Averaged by year, the highest was 26 ppb, in 2023, below EPA’s legal limit of 100 ppb. In 2025, the latest year on file, its two samples averaged 6.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15 ppb, in 2014.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

10ppb

Highest yearly average, 2022 to 2025

2025: not found

Averaged by year, the highest was 10 ppb, in 2023, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, it wasn’t found in any of its two samples.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.2ppm

Highest yearly average, 2022 to 2025

2025 average: 0.2 ppm

Averaged by year, the highest was 0.2 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its two samples averaged 0.2 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.2 ppm, in 2016.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • 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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

    Claims: Arsenic (Pentavalent)<=50 ppb Reduction, Uranium

    For: Arsenic, Uranium

    Other certifiers’ wording: 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, typically 294 mg/L (17.2 grains per gallon), across 2 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.

Softeners compared at 17.2 grains per gallon, salt includedSoftener or salt-free conditioner?California water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2026 to June 30, 20260.013 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2026 to March 31, 20260.013 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2025 to Dec. 31, 20250.013 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2025 to Sept. 30, 20250.013 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2025 to June 30, 20250.014 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2025 to March 31, 20250.013 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2024 to Dec. 31, 20240.012 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2024 to Sept. 30, 20240.011 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2023 to Sept. 30, 20230.01 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2023 to June 30, 20230.011 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2023 to March 31, 20230.011 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2022 to Dec. 31, 20220.011 MG/LArchived
ArsenicThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2022 to Sept. 30, 20220.011 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 4 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic, nitrate, chromium (total), total trihalomethanes (TTHM), fluoride and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Uranium comes from EPA’s file alone, which ends in 2019. South Kaweah Mutual Water Company’s own annual report, which it must send you every year, has newer results for those and 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. 6, 2020 to May 21, 2026; EPA’s compliance samples are from Feb. 6, 2012 to May 8, 2019.

Testing your own tap

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

  • Fruit Growers Laboratory, Inc.

    Visalia, CA · about 34 miles

    Certified for bacteria

    (559) 734-9473

  • Sierra Dairy Laboratory

    Tulare, CA · about 35 miles

    Certified for bacteria

    (559) 686-2070

  • Inyo County Water Lab

    Independence, CA · about 41 miles

    Certified for bacteria

    (760) 878-8476

All 145 certified labs for California

Sources

PWSID CA5400754. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Tulare County

All California utilities

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