Photo: David M. Green · CC BY-SA 3.0Living in Onset, MA: what to set up and who to call
Onset has no town government of its own, so Plymouth County runs its elections and most services, and its children attend Wareham School District. Onset has its own library, Spinney Branch, at 259 Onset Avenue.
I’m new in town
What to set up in Onset, 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 Onset.
Power comes from Eversource
Eversource (NSTAR Electric Co., doing business as Eversource), an investor-owned utility, serves all of Onset. Its homes paid an average of 21.5¢ per kWh in 2025, about $102 a month (its average across Massachusetts, for customers on its standard service). Massachusetts lets you buy power from another supplier; 76% of Eversource’s home customers do, and Eversource still delivers it.
Start or move service: nstar.com · (800) 592-2000
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Onset Fire Districtwater Dept.
Onset Fire Districtwater Dept. supplies Onset: about 94% of residents live in its service area. About 4% 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 5,392 people in all.
No health-based violations reported to EPA in the five years to October 2026, like 80% of the 5,012 systems serving 3,301–10,000 people.
The latest lead result on file, the 90th percentile of homes sampled in Jan 2021–Dec 2023, was 3.0 ppb, below the 15 ppb action level that applied. That’s higher than 80% 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. Violations are counted by the start of their compliance period. MA4310003.
3 home internet providers serve Onset
100% of 991 addresses can get 100/20 Mbps; 69% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Xfinity | Cable | 100% | 2,000/250 |
| Verizon | Fiber, Fixed wireless | 91% | 980/880 |
| T-Mobile | Fixed wireless | 4% | 100/20 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have Onset’s trash rules yet
Pickup rules, the dump and recycling in Onset.
Where your child goes to school
Public school districts and the school path by grade.
Onset is in Wareham 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
Onset is unincorporated, so Plymouth County is the local government.
Election office: FVAP local election office directory, updated Jun 2023; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Nov 18, 2024.
Onset spans 3 ZIP codes
ZIP codes where Onset residents live, with the share of the town in each.
| ZIP | Post office name | Share of Onset | ZIP’s residents in Onset |
|---|---|---|---|
| 02558 | Onset, MA | 91% | 68% |
| 02538 | East Wareham, MA | 8% | 3% |
| 02571 | Wareham, MA | 1% | 0% |
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 Onset
Who supplies Onset’s drinking water, and has it had violations?
Onset Fire Districtwater Dept. (EPA ID MA4310003). It reported no health-based violations to EPA in the five years to October 2026; 80% of systems its size had none. Its latest lead 90th percentile was 3.0 ppb (Jan 2021–Dec 2023), against a 15 ppb action level.
Who provides electricity in Onset?
Eversource (NSTAR Electric Co., doing business as Eversource), an investor-owned utility. Its homes paid about 21.5¢ per kWh in 2025 (EIA).
What internet providers serve Onset?
Xfinity, Verizon, T-Mobile (FCC, as of December 2025).
What ZIP codes are in Onset?
02558 (91%), 02538 (8%), 02571 (1%), by share of residents. Census 2020 ZIP Code Tabulation Areas.
What school district is Onset in?
Wareham School District.
How do I register to vote in Onset?
In Massachusetts you can register online until 10 days before Election Day, in person until 10 days before Election Day, or by mail (postmarked 10 days before). Elections here are run by the Wareham Town Clerk. Check your registration at sec.state.ma.us.
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.