Can you live off-grid in San Diego County, California?
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Major concerns
Possible, but hard and costly. Only about 17 inches of rain falls a year, so you will rely on a well or hauled water. The growing season runs about 245 frost-free days, long enough for a spring and a fall garden. The U.S. Forest Service rates wildfire risk high across much of the county, so plan cleared ground around the house.
What the land says
Rain
Too dry to live on rain. Plan on a well, and on irrigating anything you grow.
About 17 inches a year (PRISM, 1991 to 2020 average)
Wells
Well depth varies a lot here. Get a local driller's quote before you offer.
Typical well depths here range from 100 feet to 490 feet
Growing season
Long enough for a spring and a fall garden.
About 245 frost-free days, USDA zone 9a; last frost about May 19, first about October 26
Sun
Strong sun. A modest solar array covers a household.
About 6.6 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
Wildfire risk is high across much of the county. Plan cleared ground around the house and fire-resistant materials.
U.S. Forest Service wildfire hazard map: Very Low to Very High 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: high
Terrain
Steep in places. Driveways, septic, and foundations cost more.
Slopes average about 22%, about 2,350 feet above sea level
Soil
Good ground for a standard septic system. The county's soil test decides.
Loam, well 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 1 mile (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
San Diego 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.
Depends on depth, which varies here. Get a driller's quote.
Septic
$5,000 to $10,000
Standard system
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
$27,000 to $57,000
Before the house, plus the well
Before you make an offer on land here
Well depth
Get a local driller's depth estimate.
Typical well depths here range from 100 feet to 490 feet.
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.
Wildfire
Ask an insurance agent whether they will write a policy.
The U.S. Forest Service rates wildfire risk high across much of the county.
Nearby counties
3,269,973 people live in San Diego County, about 776.6 per square mile. It ranks tied for 50th of the 58 California counties we scored, and California ranks 45th of 50 states.