Off-grid site report

Lewis and Clark County, MT

46.6034, -112.0865 · 3,983 ft elevation
Read this before you act on anything below. This is my researched starting point for Lewis and Clark 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 rulesLewis and Clark County, MT

Zoning & raw-land occupancy
Varies locallyThere is no single countywide zoning ordinance; the county uses Part 1 and Part 2 zoning districts and citizen-initiated Special Zoning Districts under Montana law, administered by the county's Community Development and Planning Department. Whether raw land can be occupied off-grid depends entirely on the parcel's district. source
Dwellings, tiny homes & RVs
Unclear - verifyNo standalone county tiny-home ordinance was found; county rental-building rules reference state statute definitions for RVs and manufactured homes. Foundation-built tiny homes likely fall under the state's Appendix Q and standard county building permitting; confirm with CDP. source
Building permits & codes
RestrictedLewis and Clark County is a certified building-code jurisdiction, meaning the county's Community Development and Planning Department, not the state Building Codes Bureau, administers permitting locally. Confirm current permit thresholds and any exemptions with CDP. source
Septic & composting toilets
Generally allowedThe county's Environmental Health Division administers its own detailed On-Site Wastewater Treatment Regulations, adopted in 2016 and updated in 2020, including an active septic maintenance and inspection program, going beyond the bare state DEQ minimum. source
Greywater reuse
Unclear - verifyNo county-specific greywater ordinance was found; greywater is likely folded into the county's general onsite wastewater program administered by Environmental Health, but this is not confirmed. Ask Environmental Health directly. source
Rainwater harvesting
Unclear - verifyNo official county page was found regulating or prohibiting rooftop rainwater collection; presumed permitted for small-scale personal, non-potable use under the state baseline, but not confirmed at the county level.
Private wells & water rights
Varies locallySingle-home wells generally proceed under Montana DNRC's standard exempt-well process, but the county lies partly within legally closed river basins where new water use may require mitigation, and the exempt-well statute is currently being challenged in this county's district court. Verify current status with DNRC and the county's Environmental Health sanitarian.
Living disconnected from utilities
Unclear - verifyNo explicit county ordinance requiring grid or utility hookup was found, but county building, zoning, and septic/water permitting function as practical prerequisites for legal occupancy in most districts.

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)
2.6 hrs/day
Yearly output per 1 kW of panels
1,356 kWh
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Weather1991-2020

Precipitation
11 in/yr
Snowfall
38 in/yr
Heating degree days
7,540 (severe)
Frost-free season
May 13 to Sep 25

How far help isstraight-line

Hospital
Saint Peter's Health
4.5 mi
Fire station
Helena Fire Department
2.3 mi
Hardware store
Capital City Granite
1.1 mi
Grocery
Town & Country
2.1 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 59636).

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.