Off-grid site report
Madison County, ID
43.8258, -111.7822 · 4,879 ft elevationRead this before you act on anything below. This is my researched starting point for Madison County, ID, 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 rulesMadison County, ID
Zoning & raw-land occupancy
Unclear - verifyMadison County Planning & Zoning administers a countywide Unified Development Code, but I found no specific text on raw-land occupancy (tents, yurts, camping) rules; ask the department directly. Rexburg and Sugar City have their own separate zoning that overrides county rules inside city limits. source
Dwellings, tiny homes & RVs
Unclear - verifyManufactured/mobile homes need HUD certification and an Installation Permit under Idaho Code Title 44, Chapter 25. Tiny homes on wheels and RVs as permanent dwellings are not addressed in retrieved county text, so that's not confirmed.
Building permits & codes
RestrictedMadison County Building Department has issued its own permits since 1976 under the 2018 International Building Codes; mechanical/electrical/plumbing permits countywide are handled separately by the City of Rexburg building department. source
Septic & composting toilets
Generally allowedSeptic systems are legal with a permit and site evaluation through Eastern Idaho Public Health (or Madison County Health Department per older pages), consistent with the statewide IDAPA 58.01.03 rule requiring a valid installation permit. source
Greywater reuse
RestrictedNo Madison County-specific greywater ordinance was found; it falls under the same statewide subsurface sewage disposal rules enforced by Eastern Idaho Public Health. Not confirmed beyond that baseline.
Rainwater harvesting
Unclear - verifyNo official Madison County or Eastern Idaho Public Health page on residential rainwater catchment was found. Not confirmed either way.
Private wells & water rights
Generally allowedWell drilling is state-administered by the Idaho Department of Water Resources; a drilling permit and licensed driller are required, and domestic wells need no further IDWR approvals beyond that. source
Living disconnected from utilities
Unclear - verifyNo explicit rule bars off-grid power, but the county's occupancy process implies septic (and likely water) must be inspected and approved before a certificate of occupancy issues, per Madison County Health Department's environmental health page.
Sun30-year normals
- Peak-sun hours, annual average
- 5.0 hrs/day
- Worst month (sizes an off-grid array)
- 2.0 hrs/day
- Yearly output per 1 kW of panels
- 1,433 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 13 in/yr
- Heating degree days
- 8,129 (severe)
- Frost-free season
- May 20 to Sep 18
How far help isstraight-line
- Hospital
Madison Memorial Hospital - 0.6 mi
- Fire station
Rexburg Madison Fire Dept - 0.1 mi
- Hardware store
Dan's Ace Hardware - 0.1 mi
- Grocery
Broulim's Supermarket - 0.3 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 83460).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Madison County, ID?The rules above are the jurisdiction. The land check runs the parcel itself: flood zone, soils and septic suitability, wetlands, slope, access, climate, and these verdicts, from a parcel number or coordinates.
Check a parcel →Share or save this report:New report
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.
New here, or not sure where this fits? Start here walks through the whole thing in order.