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Las Deltas 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
375 people
Connections
75
Water source
Groundwater bought from another system
Based in
Clovis, CA
County
Fresno
Owner
Private
The ZIP code it serves

93622

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Total trihalomethanes (TTHM), above the legal limit. 12 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2007 to 2026.

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): California’s own results, samples taken from Jan. 14, 2020 to April 24, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

125ppb

Highest yearly average, 2020 to 2026

2026 average: 67.3 ppb

Averaged by year, the highest was 125 ppb, in 2024, above EPA’s legal limit of 80 ppb. Its highest single sample was 130 ppb. In 2026, the latest year on file, its three samples averaged 67.3 ppb. EPA recorded a violation for total trihalomethanes (TTHM) at this utility in 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 104 ppb, in 2019, and EPA recorded violations in 2016, 2017, 2018 and 2019.

What handles it

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

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

0.8ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 0.8 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 limits1

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

24ppb

Highest yearly average, 2020 to 2026

2026 average: 13 ppb

Averaged by year, the highest was 24 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, its two samples averaged 13 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 16.7 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

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: Trihalomethanes (TTHM) Reduction, Lead Reduction

    For: Total trihalomethanes (TTHM), Lead

    Other certifiers’ wording: VOC Reduction

  • NSF/ANSI 58

    Claims: Trihalomethanes (TTHM) Reduction, Lead Reduction

    For: Total trihalomethanes (TTHM), 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

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 20200.11 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20190.1 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2019 to June 30, 20190.11 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2019 to March 31, 20190.098 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2018 to Dec. 31, 20180.095 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2018 to Sept. 30, 20180.095 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2018 to June 30, 20180.095 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2018 to March 31, 20180.096 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2017 to Sept. 30, 20170.096 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 20170.095 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2017 to March 31, 20170.093 MG/LArchived
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2016 to Sept. 30, 20160.087 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 2 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are California’s own from 2020 on, with EPA’s national file for 2012 to 2019. Las Deltas 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 Jan. 14, 2020 to April 24, 2026.

Testing your own tap

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

  • Dellavalle Laboratory, Inc.

    Fresno, CA · about 41 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, radioactivity

    (559) 233-6129

  • Moore Twining Associates, Inc.

    Fresno, CA · about 44 miles

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

    (559) 268-7021

  • Certified Laboratories - Turlock

    Turlock, CA · about 50 miles

    Certified for bacteria

    (209) 664-1100

All 145 certified labs for California

Sources

PWSID CA1000054. Rebuilt from EPA data on Oct. 18, 2026.

Also in Fresno County

All California utilities

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