Photo: RM VM · CC BY-SA 4.0Living in Sienna, TX: what to set up and who to call
Sienna has no town government of its own, so Fort Bend County runs its elections and most services, and its children attend Fort Bend Independent School District. CenterPoint Energy delivers the power in Sienna, but in Texas’s open market you choose the company that sells it.
I’m new in town
What to set up in Sienna, and who provides it. Tap an answer for the details and where they come from.
Power, water and internet
Who to call to start service at a new address in Sienna.
Power comes from CenterPoint Energy
CenterPoint Energy (CenterPoint Energy), an investor-owned utility, serves all of Sienna.
Start or move service: centerpointenergy.com · (800) 259-5544
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Sienna MUD 3
Sienna MUD 3 supplies Sienna: about 35% of residents live in its service area. City of Missouri City serves another 29%. Sienna MUD 4 serves another 25%. About 16% of homes are outside any mapped community water system, most likely on private wells, which EPA doesn’t regulate. It buys treated ground water (EPA lists Sienna Regional MUD as seller) and serves 7,365 people in all.
No health-based violations reported to EPA in the five years to October 2026, like 80% of the 5,012 systems serving 3,301–10,000 people.
The latest lead result on file, the 90th percentile of homes sampled in Jan 2023–Dec 2025, was 0.5 ppb, below the 15 ppb action level that applied. The highest in five years was 3.1 ppb. That’s lower than 63% of similar systems’ latest results.
The system’s full record: EPA ECHO report
EPA SDWIS via Envirofacts (violations pulled Oct 9, 2026) and ECHO (lead samples, 2026Q3); service area: EPA Community Water System Service Area Boundaries v3.0. Violations are counted by the start of their compliance period. TX0790376.
8 home internet providers serve Sienna
100% of 8,440 addresses can get 100/20 Mbps; 44% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Astound Broadband | Fiber, Cable | 98% | 1,500/1,500 |
| Xfinity | Cable, Fiber | 97% | 2,000/250 |
| AT&T | Fixed wireless, Fiber | 36% | 25/3 |
| Frontier | Fiber, DSL | 5% | 7,000/7,000 |
| Ezee Fiber | Fiber | 3% | 8,000/8,000 |
| T-Mobile | Fixed wireless | 62% | 100/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have Sienna’s trash rules yet
Pickup rules, the dump and recycling in Sienna.
Where your child goes to school
Public school districts and the school path by grade.
Sienna is in Fort Bend Independent School District.
B+School gradeSee Schools →U.S. Department of Education, NCES Common Core of Data, 2024–25. Enrollment rules and registration are the district’s.
No town hall: the county runs things
Sienna is unincorporated, so Fort Bend County is the local government.
Election office: FVAP local election office directory, updated Oct 2024; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.
Sienna spans 2 ZIP codes
ZIP codes where Sienna residents live, with the share of the town in each.
| ZIP | Post office name | Share of Sienna | ZIP’s residents in Sienna |
|---|---|---|---|
| 77459 | Missouri City, TX | 97% | 25% |
| 77583 | Rosharon, TX | 3% | 2% |
Census 2020 ZIP Code Tabulation Areas, by census block; post office names: GeoNames (CC BY 4.0). ZIPs created since 2020 are missing.
Getting around, the ER and the library
One line each; the subject pages have the rest.
ER: CMS hospital data. Library: IMLS Public Libraries Survey, FY2024.
Questions about living in Sienna
Who supplies Sienna’s drinking water, and has it had violations?
Sienna MUD 3 (EPA ID TX0790376). It reported no health-based violations to EPA in the five years to October 2026; 80% of systems its size had none. Its latest lead 90th percentile was 0.5 ppb (Jan 2023–Dec 2025), against a 15 ppb action level.
Who provides electricity in Sienna?
CenterPoint Energy (CenterPoint Energy), an investor-owned utility.
What internet providers serve Sienna?
Astound Broadband, Xfinity, AT&T, Frontier, Ezee Fiber, T-Mobile (FCC, as of December 2025).
What ZIP codes are in Sienna?
77459 (97%), 77583 (3%), by share of residents. Census 2020 ZIP Code Tabulation Areas.
What school district is Sienna in?
Fort Bend Independent School District.
How do I register to vote in Sienna?
Texas has no online registration; you can register in person until 30 days before Election Day or by mail (postmarked 30 days before). Elections here are run by the Fort Bend County Early Voting Clerk. Check your registration at teamrv-mvp.sos.texas.gov.
Sources & dates
Every answer above names its source. Here they are with their dates.
- Water: EPA SDWIS (Envirofacts, pulled Oct 9, 2026), ECHO SDWA 2026Q3, EPA CWS Service Area Boundaries v3.0.
- Power: HIFLD Electric Retail Service Territories (map Aug 2023); EIA-861 final 2025.
- Trash: OpenStreetMap, Geofabrik extract of Oct 9, 2026. © OpenStreetMap contributors (ODbL).
- ZIP codes: Census 2020 ZCTA relationship files; GeoNames postal codes (CC BY 4.0).
- Schools: NCES Common Core of Data, 2024–25.
- Registration: vote.gov, updated Nov 18, 2024 (read Oct 10, 2026). Official sites and area codes: Wikidata.
- Election office: FVAP local election office directory (fetched Oct 10, 2026; each record dated), EAC EAVS 2024 jurisdictions; registration and lookup links from vote.gov’s state data, checked Oct 10, 2026.
- Internet: FCC National Broadband Map, as of December 2025.