Living in San Carlos, AZ: what to set up and who to call
An EPA health-based violation from 2025 is still open for the Scua Upper Seven Mile water system, which supplies San Carlos, and its latest lead result (5.0 ppb) was higher than 91% of similar systems’, though under the 15 ppb action level. San Carlos has no town government of its own, so Gila County runs its elections and most services, and its children attend San Carlos Unified District.
I’m new in town
What to set up in San Carlos, 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 San Carlos.
Power comes from USBIA-San Carlos Project
USBIA-San Carlos Project (USBIA-San Carlos Project), a federal utility, serves all of San Carlos. Its homes paid an average of 16.4¢ per kWh in 2025, about $142 a month (its average across Arizona).
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Scua Upper Seven Mile water system
The Scua Upper Seven Mile water system supplies San Carlos: about 64% of residents live in its service area. About 36% of homes are outside any mapped community water system, most likely on private wells, which EPA doesn’t regulate. It draws ground water and serves 8,478 people in all.
21 health-based violations reported to EPA in the five years to October 2026: a groundwater treatment requirement (Groundwater Rule) ×13, a bacteria testing requirement (Revised Total Coliform Rule) ×8, the latest beginning Jan 2026. 80% of the 5,012 systems serving 3,301–10,000 people had none. 7 older violations are still open, since 2025: a groundwater treatment requirement (Groundwater Rule), per EPA’s records.
The latest lead result on file, the 90th percentile of homes sampled in Jan 2023–Dec 2025, was 5.0 ppb, below the 15 ppb action level that applied. That’s higher than 91% 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 (EPA’s estimate). Violations are counted by the start of their compliance period. 090400114.
1 home internet providers serve San Carlos
57% of 970 addresses can get 100/20 Mbps; 57% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| San Carlos Apache Telecommunications Utility | Fiber, DSL | 100% | 100/50 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have San Carlos’ trash rules yet
Pickup rules, the dump and recycling in San Carlos.
Where your child goes to school
Public school districts and the school path by grade.
San Carlos is in San Carlos Unified District.
C−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
San Carlos is unincorporated, so Gila County is the local government.
Election office: FVAP local election office directory, updated Sep 2025; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Sep 12, 2025.
San Carlos is in ZIP code 85550
ZIP codes where San Carlos residents live, with the share of the town in each.
| ZIP | Post office name | Share of San Carlos | ZIP’s residents in San Carlos |
|---|---|---|---|
| 85550 | San Carlos, AZ | 99% | 80% |
A few homes fall in 85542.
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 San Carlos
Who supplies San Carlos’ drinking water, and has it had violations?
The Scua Upper Seven Mile water system (EPA ID 090400114). It reported 21 health-based violations to EPA in the five years to October 2026: a groundwater treatment requirement (Groundwater Rule) ×13, a bacteria testing requirement (Revised Total Coliform Rule) ×8. 80% of systems its size had none. Its latest lead 90th percentile was 5.0 ppb (Jan 2023–Dec 2025), against a 15 ppb action level.
Who provides electricity in San Carlos?
USBIA-San Carlos Project (USBIA-San Carlos Project), a federal utility. Its homes paid about 16.4¢ per kWh in 2025 (EIA).
What internet providers serve San Carlos?
San Carlos Apache Telecommunications Utility (FCC, as of December 2025).
What ZIP codes are in San Carlos?
85550. Census 2020 ZIP Code Tabulation Areas.
What school district is San Carlos in?
San Carlos Unified District.
How do I register to vote in San Carlos?
In Arizona you can register online until 29 days before Election Day, in person until 29 days before Election Day, or by mail (postmarked 29 days before). Elections here are run by the Gila County Recorder. Check your registration at my.arizona.vote.
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 Sep 12, 2025 (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.