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Shamrock Municipal Water System

What EPA’s and Texas’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
2,311 people
Connections
1,267
Water source
Groundwater
Based in
Shamrock, TX
County
Wheeler
Owner
Local government
The ZIP code it serves

79079

The short answer

1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Nitrate, above the legal limit. 1 health-based violation since 2016.

What handles it

What was found

Nitrate, arsenic, uranium, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5): Texas’s own results, samples taken from Feb. 18, 2020 to July 29, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

10.6ppm

Highest sample; found in 54 of 54

2026 average: 7.0 ppm

One sample, in 2022, was above EPA’s legal limit of 10 ppm, at 10.6 ppm. No follow-up sample at that point within 30 days is on file. In 2026, the latest year on file, its six samples averaged 7.0 ppm. EPA recorded a violation for nitrate at this utility in 2022. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 10.6 ppm, in 2015, and EPA recorded a violation in 2015.

What handles it

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

Above the health goal2

Arsenic

Comes from the source

Above the health goal

5.3ppb

Highest yearly average, 2021 to 2026

2026 average: 2.4 ppb

Averaged by year, the highest was 5.3 ppb, in 2025: below EPA’s legal limit of 10 ppb, but above its health goal of zero. Its highest single sample was 12 ppb. In 2026, the latest year on file, its three samples averaged 2.4 ppb. EPA recorded no violation for arsenic at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.2 ppb, in 2015.

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

0.9ppb

Highest yearly average, 2021

Averaged by year, the highest was 0.9 ppb, in 2021: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 1.8 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.95 ppb, in 2015.

What handles it

Below EPA’s limits4

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.24ppm

Highest yearly average, 2020 to 2026

2026 average: 0.23 ppm

Averaged by year, the highest was 0.24 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.31 ppm. In 2026, the latest year on file, its two samples averaged 0.23 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.58 ppm, in 2017.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

3.1ppb

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 3.1 ppb, in 2026, below EPA’s legal limit of 80 ppb. Its highest single sample was 3.3 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.6 ppb, in 2014.

What handles it

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

Chromium (total)

Comes from the source

Below EPA’s limits

3.5ppb

Highest yearly average, 2021 to 2025

2025: not found

Averaged by year, the highest was 3.5 ppb, in 2024, below EPA’s legal limit of 100 ppb. In 2025, 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 2.1 ppb, in 2015.

What handles it

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

1.6ppb

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 1.6 ppb, in 2026, below EPA’s legal limit of 60 ppb. Its highest single sample was 2.2 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 3.4 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • 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, Uranium

    For: Nitrate, Arsenic, Uranium

    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

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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 SampleJuly 1, 2022 to Sept. 30, 202211 MG/LResolved
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, uranium, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5) results here are Texas’s own from 2020 on, with EPA’s national file for 2012 to 2019. Shamrock Municipal Water System’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; Texas’s results run from Feb. 18, 2020 to July 29, 2026.

Testing your own tap

Shamrock Municipal Water System’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 Texas certifies.

No lab Texas certifies is within 75 miles of the area Shamrock Municipal Water System serves on the state’s list. Some take samples by mail; the state’s page lists them all.

Texas Well Owner Network, Texas A&M AgriLife Extension: Well Informed screening events, where well owners bring in water samples to be screened for common contaminants, followed by an hour-long session explaining the results. Upcoming events are on the network's calendar. Trainings, Texas Well Owner Network.

All 80 certified labs for Texas

Sources

PWSID TX2420001. Rebuilt from EPA data on Oct. 18, 2026.

Also in Wheeler County

All Texas utilities

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