Off-grid site report

Asotin County, WA

46.3393, -117.0482 · 820 ft elevation
Read this before you act on anything below. This is my researched starting point for Asotin County, WA, 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 rulesAsotin County, WA

Zoning & raw-land occupancy
Varies locallyAsotin County Building & Planning administers zoning in unincorporated areas, but I could not find the published zoning code text confirming which districts allow raw-land occupancy or off-grid dwellings. Cities of Asotin and Clarkston have separate zoning for land inside their limits. source
Dwellings, tiny homes & RVs
Varies locallyThe county requires an installation permit for manufactured/mobile homes anywhere in the county, with extra Labor & Industries inspection for pre-1976 homes. No county-specific rule on tiny houses on wheels or park-model RVs was found, so state rules likely apply by default. source
Building permits & codes
Generally allowedThe county confirms a building permit is required for outside structures like buildings, decking, or porches, enforced through Building & Planning in unincorporated areas or the relevant city department inside Asotin or Clarkston. source
Septic & composting toilets
Generally allowedThe Asotin County Health District administers septic (on-site sewage) permits under a county code built on state WAC 246-272A rules; new installs and major modifications need permits, minor repairs often don't. The ordinance may be under active revision, so confirm current requirements with ACHD. source
Greywater reuse
Unclear - verifyNo Asotin County-specific greywater rule was found. The state baseline under WAC 246-274, administered locally by the Asotin County Health District, applies by default; ask ACHD for local practice.
Rainwater harvesting
Unclear - verifyNo county-specific rainwater harvesting policy was found. State Department of Ecology guidance generally allows non-potable rainwater collection without a water right, but this isn't confirmed for Asotin County specifically. source
Private wells & water rights
Varies locallyWashington Department of Ecology's Eastern Region office handles water rights and well construction for Asotin County; small domestic wells may be exempt from full permitting, but regional watershed planning could affect exempt-well availability, so a pre-application consult with Ecology is recommended. source
Living disconnected from utilities
Unclear - verifyNo standalone county rule bans off-grid utility disconnection. In practice, legality depends on meeting the building code, getting septic approval from ACHD, and having a legal water source; there's no single off-grid permit confirmed. source

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average
4.4 hrs/day
Worst month (sizes an off-grid array)
1.9 hrs/day
Yearly output per 1 kW of panels
1,242 kWh
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Weather1991-2020

Precipitation
12 in/yr
Snowfall
11 in/yr
Heating degree days
5,169 (moderate)
Frost-free season
Apr 12 to Oct 23

How far help isstraight-line

Hospital
Tri-State Memorial Hospital
4.4 mi
Fire station
Lewiston Fire Department Station 4
3.2 mi
Hardware store
Early Bird Supply
4.4 mi
Grocery
Rosauers
4.4 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 99403).

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.