Off-grid site report

Walla Walla County, WA

46.0481, -118.3522 · 876 ft elevation

Read this before you act on anything below. This is my researched starting point for Walla Walla 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 rulesWalla Walla County, WA

Zoning & raw-land occupancy

Varies locallyWalla Walla County has countywide zoning under Title 17 of its code, administered per the state Growth Management Act. Permitted uses for raw land depend entirely on the parcel's specific zone and any critical area overlays. source

Dwellings, tiny homes & RVs

Unclear - verifyCity of Walla Walla allows tiny homes in some zones, but that's municipal, not county, code. For unincorporated county land, rules on RVs or tiny homes as permanent dwellings were not confirmed; the county does run a manufactured home compliance permit process. Call Community Development to confirm. source

Building permits & codes

Generally allowedBuilding permits are required and administered locally by the county's Building and Planning/Community Development Department, consistent with the state minimum building code baseline. The county offers an online eTRAKiT portal for permits and inspections. source

Septic & composting toilets

Generally allowedSeptic systems are permitted through the county Department of Community Health under a county ordinance and state WAC 246-272A. Since July 2023, the county requires a licensed On-Site Sewage System Designer or Professional Engineer for system design, and a special wet-season monitoring rule applies near Lewis Peak. source

Greywater reuse

Generally allowedThe county enforces the state's greywater reuse rule, WAC 246-274, for subsurface irrigation as adopted. No county-specific addition was found. source

Rainwater harvesting

Unclear - verifyNo county-specific rainwater harvesting policy was found; the state Department of Ecology's general baseline for non-potable on-site collection likely applies, but this is not confirmed at the county level.

Private wells & water rights

Varies locallyState groundwater permit exemptions under RCW 90.44.050 apply generally, but Walla Walla is a water-constrained basin with its own Pilot Local Water Management Program, and Ecology advises checking with local permitting agencies before drilling. source

Living disconnected from utilities

Unclear - verifyNo standalone county ordinance explicitly addresses full utility disconnection. Off-grid living in practice depends on separately satisfying building, septic, and water supply requirements enforced by county departments.

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 4.5 hrs/day
Worst month (sizes an off-grid array): 1.6 hrs/day
Yearly output per 1 kW of panels: 1,250 kWh

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Weather1991-2020

Precipitation: 21 in/yr
Snowfall: 12 in/yr
Heating degree days: 5,011 (moderate)
Frost-free season: Mar 30 to Oct 28

How far help isstraight-line

Hospital Providence Saint Mary Medical Center: 1.0 mi
Fire station Walla Walla Fire District Station 1: 0.8 mi
Hardware store The Home Depot: 1.0 mi
Grocery Safeway: 0.2 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 99362).

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.