Is Sienna, TX tap water safe?
The short answer
None of the 15 utilities serving Sienna has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Texas’s records.
Quail Valley Utility District, which serves the most people here, has 2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 15.7 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Sienna’s ZIP codes, from EPA’s estimates.
- Open report
Quail Valley Utility District
Texas · serves 14,409 people · about 2,900 in Sienna
2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 15.7 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
First Colony MUD 9
Texas · serves 7,818 people · about 2,400 in Sienna
2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 17.6 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Sienna MUD 10
Texas · serves 7,824 people · about 2,300 in Sienna
1 result above EPA’s health benchmark. The worst: Lithium at 19.2 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Sienna MUD 3
Texas · serves 7,365 people · about 2,300 in Sienna
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 25 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
City of Missouri City
Texas · serves 4,847 people · about 1,900 in Sienna
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 16.4 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Sienna MUD 4
Texas · serves 6,435 people · about 1,600 in Sienna
Nothing in its records is above a health goal.
No health-based violations since 2016
- Open report
Sienna MUD 12
Texas · serves 4,311 people · about 1,400 in Sienna
1 result above the health goal. The worst: Lead at 1.7 ppb, above the health goal.
No health-based violations since 2016
- Open report
City of Missouri City Mustang Bayou Wate
Texas · serves 9,147 people · about 1,400 in Sienna
2 results above the health goal. The worst: Arsenic at 2.5 ppb, above the health goal.
No health-based violations since 2016
- Open report
Fort Bend County MUD 42 Wat Plat
Texas · serves 4,395 people · about 1,300 in Sienna
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 15 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Thunderbird Utility District 1
Texas · serves 4,203 people · about 1,000 in Sienna
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 21 ppb, above EPA’s health benchmark.
No health-based violations since 2016
5 more utilities in Sienna
By EPA’s estimate, each serves fewer people in Sienna than those above.
- Fort Bend County MUD 48serves 3,969 people · about 900 in Sienna · no health-based violations since 2016
- Palmer Plantation MUD 2serves 2,559 people · about 750 in Sienna · no health-based violations since 2016
- Fort Bend County MUD 47serves 2,874 people · about 730 in Sienna · no health-based violations since 2016
- Fort Bend County MUD 46serves 2,247 people · about 700 in Sienna · no health-based violations since 2016
- Palmer Plantation MUD 1serves 2,031 people · about 560 in Sienna · no health-based violations since 2016
MUD stands for municipal utility district, a local water and sewer district common in Texas.
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in Quail Valley Utility District’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Water testing near Sienna
The 3 labs Texas certifies closest to Sienna, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Eurofins Xenco, LLC -Houston
Stafford, TX · about 12 miles
Certified for lead and copper
ALS Laboratory Group, Environmental Services Division – Houston, Texas
Houston, TX · about 16 miles
Certified for lead and copper
Envirodyne Laboratories, Inc.
Houston, TX · about 16 miles
Certified for bacteria, lead and copper
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 TexasWhich ZIP codes are in Sienna: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: TCEQ, drinking water laboratories approved for public water system samples; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Sienna
Other towns in Fort Bend County with a page of their own.
What to do next
- Read Quail Valley Utility District’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water