Living in Lake Madison, SD: what to set up and who to call
Lake Madison has no town government of its own, so Lake County runs its elections and most services, and its children attend Madison Central School District 39-2. Most of Lake Madison has one wired internet choice: Midco.
I’m new in town
What to set up in Lake Madison, 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 Lake Madison.
Power comes from Xcel Energy
Xcel Energy (Northern States Power Co. (Minnesota)), an investor-owned utility, serves all of Lake Madison. Its homes paid an average of 13.1¢ per kWh in 2025, about $101 a month (its average across South Dakota).
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 Lake Madison: about 49% 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 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.
6 home internet providers serve Lake Madison
99% of 1,059 addresses can get 100/20 Mbps; 37% can get fiber.
| Provider | Technology | Addresses | Fastest (Mbps) |
|---|---|---|---|
| Midco | Cable | 60% | 2,000/350 |
| ITC | Fiber | 38% | 1,000/1,000 |
| Interlakes Wireless | Fixed wireless | 99% | 100/20 |
| GigFire | Fixed wireless | 65% | 150/130 |
| Verizon | Fixed wireless | 64% | 300/20 |
| AT&T | Fixed wireless | 16% | 25/3 |
FCC National Broadband Map, as of December 2025. Availability as providers report it, not speeds people get.
We don’t have Lake Madison’s trash rules yet
Pickup rules, the dump and recycling in Lake Madison.
Where your child goes to school
Public school districts and the school path by grade.
Most of Lake Madison (89%) is in Madison Central School District 39-2; parts are in Chester School District 39-1 (11%).
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
Lake Madison is unincorporated, so Lake County is the local government.
Election office: FVAP local election office directory, updated Jul 2023; jurisdictions: EAC EAVS 2024. Registration rules and links: vote.gov, updated Aug 3, 2026.
Lake Madison spans 2 ZIP codes
ZIP codes where Lake Madison residents live, with the share of the town in each.
| ZIP | Post office name | Share of Lake Madison | ZIP’s residents in Lake Madison |
|---|---|---|---|
| 57075 | Wentworth, SD | 62% | 44% |
| 57042 | Madison, SD | 38% | 4% |
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 Lake Madison
Who supplies Lake Madison’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 Lake Madison?
Xcel Energy (Northern States Power Co. (Minnesota)), an investor-owned utility. Its homes paid about 13.1¢ per kWh in 2025 (EIA).
What internet providers serve Lake Madison?
Midco, ITC, Interlakes Wireless, GigFire, Verizon, AT&T (FCC, as of December 2025).
What ZIP codes are in Lake Madison?
57075 (62%), 57042 (38%), by share of residents. Census 2020 ZIP Code Tabulation Areas.
What school district is Lake Madison in?
Madison Central School District 39-2. Parts of the city are in Chester School District 39-1.
How do I register to vote in Lake Madison?
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 Lake 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.