Living in Oldham, SD: what to set up and who to call
All of Oldham gets its mail under one ZIP code, 57051. The ER is a drive from Oldham: the closest is Avera De Smet Memorial Hospital - Cah, 16.6 miles away.
I’m new in town
What to set up in Oldham, 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 Oldham.
Power comes from NorthWestern Energy
NorthWestern Energy (NorthWestern Energy - (SD)), an investor-owned utility, serves all of Oldham. Its homes paid an average of 13.3¢ per kWh in 2025, about $125 a month (its average across South Dakota).
Start or move service: northwesternenergy.com · (800) 245-6977
Service territory: HIFLD Electric Retail Service Territories (map dated Aug 2023). Prices and customers: EIA-861, 2025.
Water comes from Kingbrook I Rural Water System
Kingbrook I Rural Water System supplies almost all of Oldham. It buys treated ground water (EPA lists Brookings-Deuel Rural Water System as seller) and serves 6,455 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–Dec 2024, was 2.0 ppb, below the 15 ppb action level that applied. That’s higher than 67% 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. SD4600431.
1 home internet providers serve Oldham
100% of 95 addresses can get 100/20 Mbps; 100% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Alliance Communications Cooperative | Fiber | 100% | 1,000/1,000 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have Oldham’s trash rules yet
Pickup rules, the dump and recycling in Oldham.
Where your child goes to school
Public school districts and the school path by grade.
Oldham is in Oldham-Ramona-Rutland 39-6.
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.
Town hall and registering to vote
Who to call, and how to register.
Election office: FVAP local election office directory, updated Jul 2023; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Aug 3, 2026.
Oldham is in ZIP code 57051
ZIP codes where Oldham residents live, with the share of the town in each.
| ZIP | Post office name | Share of Oldham | ZIP’s residents in Oldham |
|---|---|---|---|
| 57051 | Oldham, SD | 100% | 49% |
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 Oldham
Who supplies Oldham’s drinking water, and has it had violations?
Kingbrook I Rural Water System (EPA ID SD4600431). 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 2.0 ppb (Jan–Dec 2024), against a 15 ppb action level.
Who provides electricity in Oldham?
NorthWestern Energy (NorthWestern Energy - (SD)), an investor-owned utility. Its homes paid about 13.3¢ per kWh in 2025 (EIA).
What internet providers serve Oldham?
Alliance Communications Cooperative (FCC, as of December 2025).
What ZIP codes are in Oldham?
57051. Census 2020 ZIP Code Tabulation Areas.
What school district is Oldham in?
Oldham-Ramona-Rutland 39-6.
How do I register to vote in Oldham?
South Dakota has no online registration; you can register in person until 15 days before Election Day or by mail (received 15 days before). Elections here are run by the Kingsbury County Auditor. Check your registration at vip.sdsos.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 Aug 3, 2026 (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.