Off-grid site report

Prairie County, MT

46.7329, -105.4252 · 2,215 ft elevation

Read this before you act on anything below. This is my researched starting point for Prairie 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 rulesPrairie County, MT

Zoning & raw-land occupancy

Unclear - verifyNo countywide zoning ordinance was found; Prairie County's Land Planning Board is advisory and the county's confirmed regulatory reach is subdivision review under state law. Occupying an existing raw parcel doesn't appear to trigger a zoning permit, but confirm with the Land Planning Board. source

Dwellings, tiny homes & RVs

Unclear - verifyNo Prairie County page addresses tiny homes or RV occupancy specifically; the state has adopted Appendix Q for small foundation-built homes and generally treats wheeled tiny homes as RVs restricted to parks or temporary siting. Confirm local practice with the county.

Building permits & codes

Varies locallyNo evidence of a local Prairie County building code department; construction likely falls under Montana's state Building Codes Program (Dept. of Labor & Industry) unless the county has opted into local enforcement, which is not confirmed. source

Septic & composting toilets

Generally allowedSeptic systems are permitted and administered locally through the Prairie County Health Department, with the Montana DEQ overoverseeing sanitation review for subdivisions. source

Greywater reuse

RestrictedNo Prairie County greywater rule was found; the state baseline allows limited in-home reuse through a compliant system but restricts subsurface irrigation reuse under state administrative rule.

Rainwater harvesting

Generally allowedNo Prairie County rule addresses rainwater collection; the state baseline does not prohibit basic rooftop collection for personal, non-potable use.

Private wells & water rights

Generally allowedNo distinct Prairie County well ordinance was found; single wells on existing land fall under Montana DNRC's exempt-well framework, though subdivision applications do require water rights documentation. source

Living disconnected from utilities

Unclear - verifyNo Prairie County ordinance requiring grid, water, or sewer hookup for an existing single-family residence was found; subdivision review does require documentation of access and water facilities but only for new subdivided lots. 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): 2.9 hrs/day
Yearly output per 1 kW of panels: 1,393 kWh

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Weather1991-2020

Precipitation: 12 in/yr
Heating degree days: 8,074 (severe)

How far help isstraight-line

Hospital Prairie Community Hospital: 6.6 mi
Fire station Terry Fire Department: 6.8 mi
Hardware store: none within range
Grocery Supervalue: 6.8 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 59349).

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