Can you live off-grid in Marin County, California?
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Significant challenges
Possible, but earthquakes will be hard. The U.S. Geological Survey maps strong earthquake shaking here, so build to the seismic code. The growing season runs about 317 frost-free days, long enough for a spring and a fall garden. The ground is steep, with slopes averaging about 19%. That raises the cost of a driveway, septic, and foundation.
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 36 inches a year (PRISM, 1991 to 2020 average)
Wells
Typical well depth. Budget for a mid-range well.
The typical well here is about 190 feet deep; a well typically runs $11,000 to $24,000
Growing season
Long enough for a spring and a fall garden.
About 317 frost-free days, USDA zone 10a; last frost about February 22, first about December 8
Sun
Good sun. Size the array and battery bank for winter.
About 5.4 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 within a quarter mile across much of the county
Wildfire
Low wildfire risk.
U.S. Forest Service wildfire hazard map: Low to Moderate 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
Steep in places. Driveways, septic, and foundations cost more.
Slopes average about 19%, about 270 feet above sea level
Soil
Expect a costlier septic system, because rock or a hard layer sits about 34 inches down. The county's soil test decides.
Loam, well drained (USDA soil survey). A mound, sand filter, or treatment unit typically runs $10,000 to $20,000
Road
Paved roads are close by.
Nearest paved road usually within about 0.5 miles (OpenStreetMap)
Check a California parcel, or plan the one you own
Get a free 0-100 off-grid score.
A step-by-step build plan, sizing your solar, water, garden, septic, heat, and buildings.
Is it legal here?
Zoning
Marin County zones land outside its towns and publishes its zoning map. Our free lookup shows the district for any address.
Building code
The California Building Standards Code (Title 24) applies statewide and every city and county must enforce it, so a new house needs a permit however remote. A county may adopt the state's optional rules for owner-built rural homes, which relax some standards but still require a permit.
Rainwater
Collecting it is allowed.
Composting toilets
Allowed with a permit and an approved unit.
Water rights
A mix of two systems. Ask the state water office before you drill a well or dam a creek.
Drilled to about 190 feet, with pump and pressure tank
Septic
$10,000 to $20,000
Mound, sand filter, or treatment unit
Solar and batteries
$18,000 to $32,000
Sized for a modest household
Road or driveway
$4,000 to $10,000
From the nearest road to a house site
Clearing
$1,000 to $5,000
A house site, solar, and garden
Total
$43,000 to $90,000
Before the house
Before you make an offer on land here
Soil test
Get a soil test before you count on septic.
Rock or a hard layer sits about 34 inches down, which can rule out a standard system.
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
Look up the parcel's zoning district with our free tool.
The county publishes its zoning map.
Nearby counties
254,407 people live in Marin County, about 489.1 per square mile. It ranks tied for 6th of the 58 California counties we scored, and California ranks 45th of 50 states.