Living in San Geronimo, CA: what to set up and who to call
San Geronimo has no town government of its own, so Marin County runs its elections and most services, and its children attend Lagunitas Elementary School District. Xfinity and AT&T both wire most of San Geronimo; 0% of addresses can get fiber.
I’m new in town
What to set up in San Geronimo, 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 Geronimo.
Power comes from PG&E
PG&E (Pacific Gas & Electric Co.), an investor-owned utility, serves all of San Geronimo. Its homes paid an average of 37.5¢ per kWh in 2025, about $174 a month (its average across California, for customers on its standard service). California lets you buy power from another supplier; 66% of PG&E’s home customers do, and PG&E still delivers it.
Start or move service: pgecorp.com
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Marin Municipal Water District
Marin Municipal Water District supplies almost all of San Geronimo. It draws surface water (EPA lists Sonoma County Water Agency as seller) and serves 186,895 people in all.
No health-based violations reported to EPA in the five years to October 2026, like 86% of the 332 systems serving 100,001–250,000 people.
The latest lead result on file, the 90th percentile of homes sampled in Jan 2019–Dec 2021, 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. CA2110002.
3 home internet providers serve San Geronimo
98% of 177 addresses can get 100/20 Mbps; 0% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Xfinity | Cable | 98% | 2,000/250 |
| AT&T | DSL, Fixed wireless | 77% | 25/3 |
| Verizon | Fixed wireless | 56% | 300/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have San Geronimo’s trash rules yet
Pickup rules, the dump and recycling in San Geronimo.
Where your child goes to school
Public school districts and the school path by grade.
San Geronimo is in two districts that split the grades: Lagunitas Elementary School District and Tamalpais Union High 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
San Geronimo is unincorporated, so Marin County is the local government.
Election office: FVAP local election office directory, updated Jul 2025; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.
San Geronimo spans 2 ZIP codes
ZIP codes where San Geronimo residents live, with the share of the town in each.
| ZIP | Post office name | Share of San Geronimo | ZIP’s residents in San Geronimo |
|---|---|---|---|
| 94963 | San Geronimo, CA | 90% | 91% |
| 94973 | Woodacre, CA | 10% | 3% |
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 Geronimo
Who supplies San Geronimo’s drinking water, and has it had violations?
Marin Municipal Water District (EPA ID CA2110002). It reported no health-based violations to EPA in the five years to October 2026; 86% of systems its size had none. Its latest lead 90th percentile was 0.0 ppb (Jan 2019–Dec 2021), against a 15 ppb action level.
Who provides electricity in San Geronimo?
PG&E (Pacific Gas & Electric Co.), an investor-owned utility. Its homes paid about 37.5¢ per kWh in 2025 (EIA).
What internet providers serve San Geronimo?
Xfinity, AT&T, Verizon (FCC, as of December 2025).
What ZIP codes are in San Geronimo?
94963 (90%), 94973 (10%), by share of residents. Census 2020 ZIP Code Tabulation Areas.
What school district is San Geronimo in?
Lagunitas Elementary School District and Tamalpais Union High School District.
How do I register to vote in San Geronimo?
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 Marin County Registrar of Voters. 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: 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.