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Charleston MUD

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
1,212 people
Connections
404
Water source
Groundwater
Based in
Houston, TX
County
Fort Bend
Owner
Local government
The ZIP code it serves

77581

The short answer

1 result is 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

Arsenic, fluoride, total trihalomethanes (TTHM), haloacetic acids (HAA5), chromium (total), nitrate and uranium: Texas’s own results, samples taken from July 19, 2022 to June 30, 2026.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

4.2ppb

Highest yearly average, 2022 to 2025

2025, one sample: 3.1 ppb

Averaged by year, the highest was 4.2 ppb, in 2022: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2025, the latest year on file, its one sample was 3.1 ppb.

What handles it

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

Below EPA’s limits3

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.77ppm

Highest yearly average, 2022 to 2025

2025, one sample: 0.76 ppm

Averaged by year, the highest was 0.77 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its one sample was 0.76 ppm.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

9.4ppb

Highest yearly average, 2022 to 2026

2026, one sample: 6.9 ppb

Averaged by year, the highest was 9.4 ppb, in 2022, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its one sample was 6.9 ppb.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

1.0ppb

Highest yearly average, 2022 to 2026

2026: not found

Averaged by year, the highest was 1.0 ppb, in 2024, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, it wasn’t found in its one sample.

What handles it

No certification claim covers this compound yet.

4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Lead
  • Nitrate
  • Uranium

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

    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

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The best reverse osmosis systems, ranked

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, fluoride, total trihalomethanes (TTHM), haloacetic acids (HAA5), chromium (total), nitrate and uranium results here are Texas’s own from 2022 on, with EPA’s national file for 2012 to 2019. Charleston MUD’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 July 19, 2022 to June 30, 2026.

Testing your own tap

Charleston MUD’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 Charleston MUD serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • City of Houston Health Department, Bureau of Laboratory Services

    Houston, TX · about 12 miles

    Certified for bacteria

    (832) 393-3939

  • A & B Environmental Services, Inc.

    Houston, TX · about 14 miles

    Certified for bacteria, lead and copper

    (713) 453-6060

  • Eurofins Xenco, LLC -Houston

    Stafford, TX · about 18 miles

    Certified for lead and copper

    (281) 240-4200

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 TX0790588. Rebuilt from EPA data on Oct. 18, 2026.

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