Sienna MUD 7

What EPA’s and Texas’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals, plus violations since 2016, with the certification that handles each result.

Serves: 69 people
Connections: 23
Water source: Surface water bought from another system
Based in: Houston, TX
County: Fort Bend
Owner: Local government

The short answer

Nothing in EPA’s and Texas’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, not everything. No health-based violations on file since 2016.

What was found

Total trihalomethanes (TTHM), nitrate and haloacetic acids (HAA5): Texas’s own results, samples taken from Feb. 24, 2026 to Sept. 28, 2026.

Below EPA’s limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

30.8ppb

Highest yearly average, 2026

Averaged by year, the highest was 30.8 ppb, in 2026, below EPA’s legal limit of 80 ppb. That is the only year on file.

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

2.2ppm

Highest sample; found in 3 of 3

2026 average: 1.4 ppm

The highest sample, in 2026, was 2.2 ppm, below EPA’s legal limit of 10 ppm. That is the only year on file, and its three samples averaged 1.4 ppm.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

5.3ppb

Highest yearly average, 2026

Averaged by year, the highest was 5.3 ppb, in 2026, below EPA’s legal limit of 60 ppb. That is the only year on file.

What handles it

No certification claim covers this compound yet.

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

Everything else. Total trihalomethanes (TTHM), nitrate and haloacetic acids (HAA5) results here are Texas’s own from 2026 on, with EPA’s national file for 2012 to 2019. Sienna MUD 7’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. 24, 2026 to Sept. 28, 2026.

Testing your own tap

Sienna MUD 7’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 Sienna MUD 7 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