Off-grid site report

Dewey County, SD

45.3725, -100.6447 · 1,732 ft elevation

Read this before you act on anything below. This is my researched starting point for Dewey County, SD, not legal advice and not a guarantee. Rules change, and the deciding facts on any specific parcel (setbacks, perc results, overlay districts, deed restrictions, road frontage) live at the county or town office, not in any database. Before you buy land or build, confirm the current rules directly with the local zoning and health offices - the sources on this page tell you exactly who to call.

The local rulesDewey County, SD

Zoning & raw-land occupancy

Unclear - verifyNot confirmed whether Dewey County has adopted a zoning ordinance. State law (SDCL 11-2) lets counties adopt zoning but doesn't require it, and much of the county is tribal trust land outside county zoning authority anyway. source

Dwellings, tiny homes & RVs

Unclear - verifyNo Dewey County-specific rule on tiny homes, minimum square footage, or RV occupancy was found; this would fall under local zoning if adopted, which is unconfirmed here.

Building permits & codes

Unclear - verifyNot confirmed whether Dewey County requires building permits. South Dakota has no statewide residential building code, and many rural counties have no local permit requirement, but that hasn't been confirmed specifically for Dewey County. source

Septic & composting toilets

Generally allowedOn-site wastewater systems are regulated statewide by South Dakota under Administrative Rules Chapter 74:53:01, typically requiring a certified installer; local Dewey County administration details are not confirmed.

Greywater reuse

Unclear - verifyNo statewide DANR rule or Dewey County ordinance on greywater reuse was found. Ask the county or the state DANR Surface Water Quality Program directly.

Rainwater harvesting

Unclear - verifyNo explicit South Dakota statute or Dewey County rule on rainwater harvesting was found; small residential catchment likely falls under the state's domestic water-use exemption but this isn't explicitly confirmed. source

Private wells & water rights

Generally allowedWells are regulated statewide by South Dakota DANR under Well Construction Standards, and domestic use is generally exempt from needing a water rights permit unless it exceeds set thresholds; no Dewey County-specific addition was found. source

Living disconnected from utilities

Varies locallyNo South Dakota law or confirmed Dewey County rule prohibits disconnecting from utilities; electrical work is licensed statewide with an owner's exemption typically available for one's own residence.

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 5.0 hrs/day
Worst month (sizes an off-grid array): 3.0 hrs/day
Yearly output per 1 kW of panels: 1,455 kWh

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Weather1991-2020

Precipitation: 16 in/yr
Snowfall: 31 in/yr
Heating degree days: 7,856 (severe)
Frost-free season: May 1 to Oct 7

How far help isstraight-line

Hospital Mobridge Regional Hospital: 15.3 mi
Fire station: none within range
Hardware store Ace Hardware: 15.2 mi
Grocery Payless Foods: 15.3 mi

From OpenStreetMap. Road miles will be longer, often much longer in hill country.

Plan this spot

These open with this location's real numbers already filled in (ZIP 57657).

Size a solar system Heat loss & insulation Firewood per winter Rainwater harvest Garden size Panel tilt

Sources: US Census Bureau geocoder; NLR PVWatts v8 (solar); NOAA NCEI 1991-2020 climate normals (nearest station) or Open-Meteo (ZIP-centroid) for weather; Open-Elevation; OpenStreetMap contributors. Public data retrieved Aug 22, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.