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City of Mabton

What EPA’s and Washington’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
2,150 people
Connections
636
Water source
Groundwater
Based in
Mabton, WA
County
Yakima
Owner
Local government
Hardness
Hard
The ZIP code it serves

98935

The short answer

3 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2000 to 2024.

Arsenic, uranium, total trihalomethanes (TTHM), fluoride, haloacetic acids (HAA5), chromium (total) and nitrate: Washington’s own results, samples taken from June 10, 2020 to Sept. 8, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal3

Arsenic

Comes from the source

Above the health goal

5.3ppb

Highest yearly average, 2020 to 2023

2023 average: 1.0 ppb

Averaged by year, the highest was 5.3 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 7.0 ppb. In 2023, the latest year on file, its two samples averaged 1.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 14.1 ppb, in 2018.

What handles it

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

Uranium

Comes from the source

Above the health goal

8.4ppb

Highest yearly average, 2022 to 2023

Averaged by year, the highest was 8.4 ppb, in 2023: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 13.5 ppb, in 2013.

What handles it

Lead

Comes from pipes, often your own

Above the health goal

2.0ppb

90th percentile, 2022 to 2024

In the latest period, 9 in 10 homes sampled were at or below 2.0 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 limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

25.2ppb

Highest yearly average, 2020 to 2026

2026, one sample: 24.8 ppb

Averaged by year, the highest was 25.2 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its one sample was 24.8 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 44.1 ppb, in 2018.

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

0.59ppm

Highest yearly average, 2022 to 2025

Averaged by year, the highest was 0.59 ppm, in 2025, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.98 ppm, in 2012.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

7.1ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 7.1 ppb, in 2021, below EPA’s legal limit of 60 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 10.8 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.
  • Chromium (total)
  • Nitrate

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: Arsenic (Pentavalent)<=50 ppb Reduction, Lead Reduction

    For: Arsenic, Lead

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

  • NSF/ANSI 58

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

    For: Arsenic, Uranium, Lead

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

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 reverse osmosis systems, ranked

The best water filters for lead, ranked

Hardness

Hard, 128 mg/L (7.5 grains per gallon), at its one sampling point, in 2022.

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 7.5 grains per gallon, salt includedSoftener or salt-free conditioner?Washington water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016. There are 11 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, uranium, total trihalomethanes (TTHM), fluoride, haloacetic acids (HAA5), chromium (total) and nitrate results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of Mabton’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; Washington’s results run from June 10, 2020 to Sept. 8, 2026.

Testing your own tap

City of Mabton’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 Washington certifies.

The 3 labs Washington certifies closest to the area City of Mabton serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Ag Health Laboratories, Inc.

    Sunnyside, WA · about 33 miles

    Certified for bacteria, nitrate

    (509) 836-2020

  • Klickitat County Goldendale Lab

    Goldendale, WA · about 38 miles

    Certified for bacteria

    (509) 493-6211

  • Energy NW Environmental (PPL) Lab

    Richland, WA · about 39 miles

    Certified for bacteria

    (509) 372-5429

All 84 certified labs for Washington

Sources

PWSID WA5349650. Rebuilt from EPA data on Oct. 18, 2026.

Also in Yakima County

All Washington utilities

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