Off-grid site report
Thurston County, WA
47.0376, -122.9398 · 148 ft elevationRead this before you act on anything below. This is my researched starting point for Thurston 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 rulesThurston County, WA
Zoning & raw-land occupancy
Varies locallyThurston County has countywide zoning under Title 20 TCC with rural density classes like one unit per 5 acres or one unit per 20 acres; whether raw land can be occupied depends on the parcel's specific zone and legal lot status. source
Dwellings, tiny homes & RVs
RestrictedThe county treats tiny homes on wheels as park-model RVs, not allowed for permanent residence outside an RV park; RV living on private land is heavily regulated; ADUs (one per rural lot, up to 1,000-1,200 sf) are the county's supported alternative but need approved water and septic. source
Building permits & codes
Generally allowedThe county administers the state building code locally and layers on a federal Endangered Species Act HCP review for permit issuance; small unpermitted structures like sheds under 400 sf without utilities may be exempt. source
Septic & composting toilets
Generally allowedThe Thurston County Board of Health and Environmental Health Division regulate septic systems statewide-consistent, requiring permits, Operational Certificates in some areas, and Time of Transfer inspections. source
Greywater reuse
Unclear - verifyNo Thurston County-specific greywater page was found; the state WAC 246-274 baseline likely applies, and a possible pending local rule was referenced but not confirmed on a county site. Ask Environmental Health directly.
Rainwater harvesting
Unclear - verifyNo Thurston County restriction on rainwater harvesting was found; state Department of Ecology policy is presumed to govern, but this is not confirmed at the county level.
Private wells & water rights
Varies locallyThurston County still issues Certificates of Water Availability for permit-exempt single-family wells, but new applications require a state-mandated fee split with Ecology and county approval of the well site via a Supplemental Application. source
Living disconnected from utilities
RestrictedThere's no direct ban on disconnecting from utilities, but building permits require proof of approved water and septic, so full off-grid occupancy of a new dwelling is gated by that approval chain. source
Sun30-year normals
- Peak-sun hours, annual average
- 3.7 hrs/day
- Worst month (sizes an off-grid array)
- 1.5 hrs/day
- Yearly output per 1 kW of panels
- 1,025 kWh
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Weather1991-2020
- Precipitation
- 50 in/yr
- Snowfall
- 11 in/yr
- Heating degree days
- 5,384 (moderate)
- Frost-free season
- Apr 29 to Oct 14
How far help isstraight-line
- Hospital
Mason General Hospital - 15.4 mi
- Fire station
Olympia Fire Department - 2.5 mi
- Hardware store
Harbor Freight Tools - 0.1 mi
- Grocery
Haggen - 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 98504).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Thurston County, WA?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 22, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.