Off-grid site report

Yellowstone County, MT

45.7439, -108.5630 · 3,183 ft elevation
Read this before you act on anything below. This is my researched starting point for Yellowstone County, MT, 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 rulesYellowstone County, MT

Zoning & raw-land occupancy
Varies locallyThere's no single countywide zoning code. Yellowstone County's Zoning Commission covers an unincorporated area within about 4.5 miles of Billings, and a separate Laurel-Yellowstone County board covers land about a mile beyond Laurel's city limits. Land outside these mapped zones may be unzoned, but that's not confirmed without checking the specific parcel with the Planning Division. source
Dwellings, tiny homes & RVs
Unclear - verifyNo Yellowstone County-specific ordinance on tiny homes or RV dwelling was found; this likely defers to the state IRC Appendix Q baseline and whatever local zoning district, if any, covers the parcel. source
Building permits & codes
RestrictedThe City of Billings stopped issuing building, plumbing, mechanical, and electrical permits outside its city limits back in 2003, and Yellowstone County does not run a building-inspection program for rural areas. Where no local program exists, Montana's Building Codes Program (Dept. of Labor & Industry) is the default statewide authority. source
Septic & composting toilets
Generally allowedRiverStone Health, the joint city-county health department, requires inspection and permitting of all new or repaired septic systems countywide. Parcels under 20 acres go through Montana DEQ review; parcels of 20 acres or more go through the local review process instead. source
Greywater reuse
Unclear - verifyNo Yellowstone County or RiverStone Health page specifically addresses greywater reuse; this defers to the statewide Montana DEQ administrative rule baseline, so confirm current state rules directly with DEQ.
Rainwater harvesting
Unclear - verifyI found no Yellowstone County or RiverStone Health ordinance restricting basic rooftop rainwater collection, but nothing explicitly permits it either, so it defaults to the state baseline.
Private wells & water rights
Generally allowedPrivate wells fall under Montana DNRC's statewide exempt-well framework. RiverStone Health's subdivision review process can pull in DEQ water/wastewater checklists for certain subdivided parcels, but no separate county well permit was found. source
Living disconnected from utilities
Unclear - verifyNo explicit grid-connection mandate was found. Because Yellowstone County doesn't issue building permits or certificates of occupancy outside Billings, there's no permit-triggered utility-connection requirement documented for rural parcels, though septic (and sometimes DEQ water review) still apply regardless of grid status. source

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average
4.8 hrs/day
Worst month (sizes an off-grid array)
2.8 hrs/day
Yearly output per 1 kW of panels
1,365 kWh
JFMAMJJASOND

Weather1991-2020

Precipitation
15 in/yr
Snowfall
46 in/yr
Heating degree days
6,857 (cold)
Frost-free season
May 9 to Oct 1

How far help isstraight-line

Hospital
Billings Clinic
4.0 mi
Fire station
Fire Station No 5
1.2 mi
Hardware store
Magic City Granite Company
0.2 mi
Grocery
Walmart Supercenter
1.3 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 59102).

Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt

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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 21, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.