Off-grid site report

Fergus County, MT

47.3308, -109.0671 · 3,803 ft elevation

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

Zoning & raw-land occupancy

Varies locallyFergus County has no countywide zoning ordinance; the Planning Office instead reviews subdivisions, floodplain issues, and Development Permits. Towns like Lewistown, Moore, and Denton have their own arrangements. source

Dwellings, tiny homes & RVs

Unclear - verifyNo county-specific rule on tiny homes or RVs was found; a Development Permit is required before building, and the state baseline likely fills remaining gaps. Confirm with the Planning Office. source

Building permits & codes

Varies locallyFergus County does not appear to run its own certified building code program, so the state Building Codes Program likely applies, which exempts certain structures like farm buildings and small residential buildings in uncertified areas. The county Development Permit for land use is required regardless. source

Septic & composting toilets

Generally allowedThe Fergus County Health Department administers septic permits locally under state sizing standards, requiring an application and site evaluation before approval. source

Greywater reuse

Unclear - verifyNo county-specific greywater ordinance was found; the county's septic rules mention subsurface irrigation systems which may cover greywater reuse, but this isn't explicit. Ask the County Sanitarian to confirm.

Rainwater harvesting

Generally allowedNo Fergus County restriction was found on basic rooftop rainwater collection for personal, non-potable use; this follows the state baseline.

Private wells & water rights

Generally allowedNo county-specific well ordinance exists beyond noting wells on Development Permit site plans; well permitting and exempt-well status run through the state DNRC framework.

Living disconnected from utilities

Unclear - verifyNo explicit Fergus County requirement to connect to grid, water, or sewer utilities was found for a private residence; the Development Permit process functions as a de facto minimum review. source

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 4.7 hrs/day
Worst month (sizes an off-grid array): 2.4 hrs/day
Yearly output per 1 kW of panels: 1,377 kWh

JFMAMJJASOND

Weather1991-2020

Precipitation: 13 in/yr
Snowfall: 37 in/yr
Heating degree days: 7,648 (severe)
Frost-free season: May 16 to Sep 21

How far help isstraight-line

Hospital Central Montana Medical Center: 25.8 mi
Fire station Roy Fire Department: 5.0 mi
Hardware store Ace Hardware: 24.1 mi
Grocery Albertsons: 24.8 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 59471).

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.