Elmshaven · Photo: Frank Schulenburg · CC BY-SA 4.0Living in Deer Park, CA: what to set up and who to call
Deer Park has no town government of its own, so Napa County runs its elections and most services, and its children attend St. Helena Unified School District. Howell Mountain Mutual Water Company reported one health-based violation to EPA in the last five years: disinfection byproducts (TTHM), beginning Jan 2023.
I’m new in town
What to set up in Deer Park, 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 Deer Park.
Power comes from PG&E
PG&E (Pacific Gas & Electric Co.), an investor-owned utility, serves all of Deer Park. 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 Howell Mountain Mutual Water Company
Howell Mountain Mutual Water Company supplies Deer Park: about 44% of residents live in its service area. Adventist Health - St. Helena Hospital serves another 19%. About 31% 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 1,240 people in all.
1 health-based violation reported to EPA in the five years to October 2026: disinfection byproducts (TTHM), beginning Jan 2023. 78% of the 7,966 systems serving 1,001–3,300 people had none.
The latest lead result on file, the 90th percentile of homes sampled in Jan 2022–Dec 2024, 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. CA2810001.
4 home internet providers serve Deer Park
87% of 444 addresses can get 100/20 Mbps; 0% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Xfinity | Cable | 84% | 1,200/35 |
| AT&T | Fixed wireless, DSL | 22% | 25/3 |
| Valley Internet | Fixed wireless | 70% | 150/75 |
| Verizon | Fixed wireless | 25% | 300/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have Deer Park’s trash rules yet
Pickup rules, the dump and recycling in Deer Park.
Where your child goes to school
Public school districts and the school path by grade.
Most of Deer Park (91%) is in St. Helena Unified School District; parts are in Howell Mountain Elementary School District (9%).
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
Deer Park is unincorporated, so Napa 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 Nov 18, 2024.
Deer Park spans 3 ZIP codes
ZIP codes where Deer Park residents live, with the share of the town in each.
| ZIP | Post office name | Share of Deer Park | ZIP’s residents in Deer Park |
|---|---|---|---|
| 94574 | Saint Helena, CA | 85% | 13% |
| 94576 | Deer Park, CA | 11% | 100% |
| 94508 | Angwin, CA | 4% | 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 Deer Park
Who supplies Deer Park’s drinking water, and has it had violations?
Howell Mountain Mutual Water Company (EPA ID CA2810001). It reported 1 health-based violation to EPA in the five years to October 2026: disinfection byproducts (TTHM). 78% of systems its size had none. Its latest lead 90th percentile was 0.0 ppb (Jan 2022–Dec 2024), against a 15 ppb action level.
Who provides electricity in Deer Park?
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 Deer Park?
Xfinity, AT&T, Valley Internet, Verizon (FCC, as of December 2025).
What ZIP codes are in Deer Park?
94574 (85%), 94576 (11%), 94508 (4%), by share of residents. Census 2020 ZIP Code Tabulation Areas.
What school district is Deer Park in?
St. Helena Unified School District. Parts of the city are in Howell Mountain Elementary School District.
How do I register to vote in Deer Park?
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 Napa County Election Division. 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.