Living in El Castillo, TX: what to set up and who to call
An EPA health-based violation from 2025 is still open for the City of La Grulla water system, which supplies El Castillo. El Castillo has no town government of its own, so Starr County runs its elections and most services, and its children attend Rio Grande City Grulla Independent School District.
I’m new in town
What to set up in El Castillo, 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 El Castillo.
Power comes from Magic Valley Electric Coop
Magic Valley Electric Coop (Magic Valley Electric Coop Inc), a cooperative utility, serves all of El Castillo. Its homes paid an average of 10.5¢ per kWh in 2025, about $140 a month (its average across Texas).
Start or move service: magicvalley.coop · (866) 225-5683
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from City of La Grulla water system
The City of La Grulla water system supplies almost all of El Castillo. It draws surface water and serves 9,500 people in all.
12 health-based violations reported to EPA in the five years to October 2026: a surface water treatment requirement (Interim Enhanced Surface Water Treatment Rule) ×5, a bacteria testing requirement (Revised Total Coliform Rule) ×4, disinfection byproducts (TTHM) ×2, a lead and copper treatment requirement (Lead and Copper Rule Revisions), the latest beginning Jan 2026. 80% of the 5,012 systems serving 3,301–10,000 people had none. 5 older violations are still open, since 2025: a bacteria testing requirement (Revised Total Coliform Rule), per EPA’s records.
The latest lead result on file, the 90th percentile of homes sampled in Jul–Dec 2025, was 0.0 ppb, below the 15 ppb action level that applied. Results below detection are reported as 0, so 0 doesn’t mean no lead at any tap.
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. TX2140006.
5 home internet providers serve El Castillo
100% of 60 addresses can get 100/20 Mbps; 82% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Spectrum | Cable | 100% | 1,000/1,000 |
| Frontier | Fiber | 82% | 7,000/7,000 |
| AT&T | Fixed wireless | 92% | 25/3 |
| VTX1 | Fixed wireless | 92% | 300/50 |
| Verizon | Fixed wireless | 90% | 300/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have El Castillo’s trash rules yet
Pickup rules, the dump and recycling in El Castillo.
Where your child goes to school
Public school districts and the school path by grade.
El Castillo is in Rio Grande City Grulla Independent School District.
Test scores and every school: see 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
El Castillo is unincorporated, so Starr County is the local government.
Election office: FVAP local election office directory, updated May 2022; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.
El Castillo is in ZIP code 78582
ZIP codes where El Castillo residents live, with the share of the town in each.
| ZIP | Post office name | Share of El Castillo | ZIP’s residents in El Castillo |
|---|---|---|---|
| 78582 | Rio Grande City, TX | 100% | 1% |
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 El Castillo
Who supplies El Castillo’s drinking water, and has it had violations?
The City of La Grulla water system (EPA ID TX2140006). It reported 12 health-based violations to EPA in the five years to October 2026: a surface water treatment requirement (Interim Enhanced Surface Water Treatment Rule) ×5, a bacteria testing requirement (Revised Total Coliform Rule) ×4, disinfection byproducts (TTHM) ×2, a lead and copper treatment requirement (Lead and Copper Rule Revisions). 80% of systems its size had none. Its latest lead 90th percentile was 0.0 ppb (Jul–Dec 2025), against a 15 ppb action level.
Who provides electricity in El Castillo?
Magic Valley Electric Coop (Magic Valley Electric Coop Inc), a cooperative utility. Its homes paid about 10.5¢ per kWh in 2025 (EIA).
What internet providers serve El Castillo?
Spectrum, Frontier, AT&T, VTX1, Verizon (FCC, as of December 2025).
What ZIP codes are in El Castillo?
78582. Census 2020 ZIP Code Tabulation Areas.
What school district is El Castillo in?
Rio Grande City Grulla Independent School District.
How do I register to vote in El Castillo?
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 Starr 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.