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Mostyn Manor

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
2,058 people
Connections
686
Water source
Groundwater
Based in
Magnolia, TX
County
Montgomery
Owner
Private
The ZIP code it serves

77354

The short answer

1 result is above the health goal. The worst: Uranium, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Uranium, fluoride, total trihalomethanes (TTHM), nitrate, arsenic, chromium (total) and haloacetic acids (HAA5): Texas’s own results, samples taken from Aug. 12, 2020 to Sept. 8, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Uranium

Comes from the source

Above the health goal

2.4ppb

Highest yearly average, 2021 to 2024

2024: not found

Averaged by year, the highest was 2.4 ppb, in 2021: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 4.7 ppb. In 2024, 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 4.8 ppb, in 2014.

What handles it

Below EPA’s limits3

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.38ppm

Highest yearly average, 2021 to 2025

2025: not found

Averaged by year, the highest was 0.38 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. 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 0.34 ppm, in 2018.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

3.4ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 3.4 ppb, in 2023, below EPA’s legal limit of 80 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 2.2 ppb, in 2019.

What handles it

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

Nitrate

Comes from the source

Below EPA’s limits

0.11ppm

Highest sample; found in 8 of 14

2026: not found

The highest sample, in 2021, was 0.11 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, it wasn’t found in any of its two samples. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.09 ppm, in 2014.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • 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.”

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

None of the filters TapBuff has checked so far carry these claims. Search the certifier listings for the claim above.

Compare five-year costs

Violations since 2016

No health-based violations on file with EPA since 2016. There are 3 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Uranium, fluoride, total trihalomethanes (TTHM), nitrate, arsenic, chromium (total) and haloacetic acids (HAA5) results here are Texas’s own from 2020 on, with EPA’s national file for 2012 to 2019. Mostyn Manor’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 Aug. 12, 2020 to Sept. 8, 2026.

Testing your own tap

Mostyn Manor’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.

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

  • Nova Biologicals, Inc.

    Conroe, TX · about 14 miles

    Certified for bacteria

    (936) 756-5333

  • Water Utility Services, Inc.

    Spring, TX · about 15 miles

    Certified for bacteria

    (281) 290-0704

  • Eurofins EMLab P&K – Houston

    Houston, TX · about 25 miles

    Certified for bacteria

    (281) 940-2580

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 TX1700669. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Montgomery County

All Texas utilities

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