Living in Walnut, CA: what to set up and who to call
All of Walnut gets its mail under one ZIP code, 91789. Spectrum and Frontier both wire most of Walnut; 77% of addresses can get fiber.
I’m new in town
What to set up in Walnut, 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 Walnut.
Power comes from Southern California Edison
Southern California Edison (Southern California Edison Co), an investor-owned utility, serves all of Walnut. Its homes paid an average of 31.5¢ per kWh in 2025, about $149 a month (its average across California, for customers on its standard service). California lets you buy power from another supplier; 30% of Southern California Edison’s home customers do, and Southern California Edison still delivers it.
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Three Valleys Mwd water system
The Three Valleys Mwd water system supplies Walnut: about 50% of residents live in its service area. About 50% of homes are outside any mapped community water system, most likely on private wells, which EPA doesn’t regulate. It draws surface water and serves 0 people in all.
No health-based violations reported to EPA in the five years to October 2026, like 78% of the 11,392 systems serving <=100 people.
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. CA1910041.
5 home internet providers serve Walnut
99% of 8,991 addresses can get 100/20 Mbps; 77% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Spectrum | Cable, Fiber | 98% | 1,000/35 |
| Frontier | Fiber, DSL | 77% | 7,000/7,000 |
| T-Mobile | Fixed wireless | 73% | 100/20 |
| Verizon | Fixed wireless | 70% | 300/20 |
| AT&T | Fixed wireless | 53% | 100/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
Valley Vista Services picks up trash in Walnut
Pickup days, the drop-off and recycling in Walnut, from the town’s own site.
Accepted at the curb
- Old corrugated cardboard
- Bi-metallic cans
- Tin cans
- Clear or colored glass
- All plastic containers
RePlanet
350 N Lemon Ave, Walnut CA 91789
rePlanet
1180 S. Diamond Bar Blvd., Diamond Bar
We couldn’t find pickup days or drop-off hours. Check walnutca.gov →
From walnutca.gov, the town’s official site, checked Oct 23, 2026; pages dated February 1, 2026. Rules change: the town’s page is the last word. .
Where your child goes to school
Public school districts and the school path by grade.
Most of Walnut (73%) is in Walnut Valley Unified School District; parts are in Rowland Unified School District (25%) and Covina-Valley Unified School District (3%).
A−School gradeSee Schools →U.S. Department of Education, NCES Common Core of Data, 2024–25. Enrollment rules and registration are the district’s.
Town hall and registering to vote
Who to call, and how to register.
Election office: FVAP local election office directory, updated Sep 2025; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.
Walnut is in ZIP code 91789
ZIP codes where Walnut residents live, with the share of the town in each.
| ZIP | Post office name | Share of Walnut | ZIP’s residents in Walnut |
|---|---|---|---|
| 91789 | Walnut, CA | 100% | 69% |
91788 is P.O. box or single-organization ZIP with no homes.
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 Walnut
Who supplies Walnut’s drinking water, and has it had violations?
The Three Valleys Mwd water system (EPA ID CA1910041). It reported no health-based violations to EPA in the five years to October 2026; 78% of systems its size had none.
Who provides electricity in Walnut?
Southern California Edison (Southern California Edison Co), an investor-owned utility. Its homes paid about 31.5¢ per kWh in 2025 (EIA).
What internet providers serve Walnut?
Spectrum, Frontier, T-Mobile, Verizon, AT&T (FCC, as of December 2025).
What ZIP codes are in Walnut?
91789. Census 2020 ZIP Code Tabulation Areas.
What school district is Walnut in?
Walnut Valley Unified School District. Parts of the city are in Rowland Unified School District and Covina-Valley Unified School District.
How do I register to vote in Walnut?
In California you can register online until 15 days before Election Day, in person up to and including Election Day, or by mail (postmarked 15 days before). Elections here are run by the Los Angeles Registrar-Recorder County Clerk. Check your registration at voterstatus.sos.ca.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: Walnut’s own website (walnutca.gov), read Oct 23, 2026, pickup and drop-off facts extracted and checked against the page they came from.
- 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.