Best States / Washington / San Juan County

San Juan County, WA · off-grid fact sheet

Can you live off-grid in San Juan County, Washington?

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Major concerns

Possible, but hard and costly. The U.S. Geological Survey maps strong earthquake shaking here, so build to the seismic code. The growing season runs about 283 frost-free days, long enough for a spring and a fall garden. Solar is weaker here, about 3.8 hours of full sun a day, so plan a bigger battery bank or a generator.

What the land says

Rain
Rain helps, but plan on a well for most of your water and on watering the garden in dry months.
About 27 inches a year (PRISM, 1991 to 2020 average)
Wells
Typical well depth. Budget for a mid-range well.
The typical well here is about 160 feet deep; a well typically runs $9,000 to $19,000
Growing season
Long enough for a spring and a fall garden.
About 283 frost-free days, USDA zone 9a; last frost about February 19, first about November 29
Sun
Weak sun. Solar needs a generator behind it in winter.
About 3.8 hours of full sun a day, averaged over the year
Flood
Flood zones run along creeks and rivers here. Look up the parcel on FEMA's flood map.
FEMA maps flood zones in places
Wildfire
Low wildfire risk.
U.S. Forest Service wildfire hazard map: Very Low here
Storms
Hurricanes and strong tornadoes are rare here.
NOAA: no hurricane-strength storm within 50 miles since 1975; no strong (EF2 or stronger) tornado within 25 miles since 1990
Earthquakes
Strong shaking is possible. Build to the seismic code and brace the water tank.
USGS seismic hazard map: very high
Terrain
Rolling ground. Look for a flat house site.
Slopes average about 9%, about 40 feet above sea level
Soil
Good ground for a standard septic system. The county's soil test decides.
Loam, somewhat excessively drained (USDA soil survey). A standard system typically runs $5,000 to $10,000
Road
Paved roads are close by.
Nearest paved road usually within about 0.5 miles (OpenStreetMap)

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Is it legal here?

Zoning
We found no public zoning map for San Juan County, so call the county planning office with the parcel number to ask whether the land is zoned.
Building code
Washington's State Building Code, which includes the International Residential Code for homes, is in effect in every county and city. Counties and cities enforce it, so a new house needs a building permit and inspections anywhere in the state, and a local change to the rules for homes needs State Building Code Council approval.
Rainwater
Collecting it is allowed.
Composting toilets
Allowed.
Water rights
Water belongs to whoever claimed it first. A new well or pond may need a state permit, and a creek may already be claimed.

Look up a parcel's zoning free, or read Is it legal to live off-grid in Washington? for permits, septic, wells, and the counties that opt out.

What it costs to set up a homestead here

Well
$9,000 to $19,000
Drilled to about 160 feet, with pump and pressure tank
Septic
$5,000 to $10,000
Standard system
Solar and batteries
$17,000 to $31,000
Sized for a modest household
Road or driveway
$3,000 to $9,000
From the nearest road to a house site
Clearing
$1,000 to $4,000
A house site, solar, and garden
Total
$34,000 to $73,000
Before the house

Before you make an offer on land here

Flood map
Look up the parcel on FEMA's flood map.
Flood zones run along creeks and rivers here. Building in one means flood insurance and extra permits.
Zoning
Call the county planning office with the parcel number.
There is no public zoning map, so we cannot tell whether the land is zoned.
Soil test
Get a soil test before you count on septic.
The county has to approve the ground before it issues a septic permit.

Nearby counties

18,566 people live in San Juan County, about 106.8 per square mile. It ranks 32nd of the 39 Washington counties we scored, and Washington ranks 44th of 50 states.

Island County, WA · Skagit County, WA · Clallam County, WA · Whatcom County, WA · Jefferson County, WA · Kitsap County, WA · All scored Washington counties

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Sources: FEMA flood maps, USGS and state driller well records, USGS brackish groundwater study, USDA soil survey, USGS 3DEP elevation, U.S. Forest Service wildfire hazard, USGS seismic hazard, USGS PAD-US public land, U.S. Census housing counts, USDA county land values, FCC broadband map, CMS hospital list. Rainfall: PRISM Group, Oregon State University, prism.oregonstate.edu (1991-2020 normals, 4 km grid; accessed 2026-09-17). Temperatures: PRISM Group, Oregon State University, prism.oregonstate.edu (1991-2020 temperature normals, 4 km grid; accessed 2026-09-26). Storms: NOAA hurricane tracks (HURDAT2, 1975-2025) and Storm Prediction Center tornado paths (EF2+, 1990-2025). Roads: © OpenStreetMap contributors. Data updated September 2026.