Can you live off-grid in Cowlitz County, Washington?
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Major concerns
Possible, but hard and costly. The ground is steep, with slopes averaging about 26%. That raises the cost of a driveway, septic, and foundation. Water is easy here, with about 74 inches of rain a year and wells near 100 feet. Solar is weaker here, about 3.6 hours of full sun a day, so plan a bigger battery bank or a generator.
What the land says
Rain
Rain can supply much of a household's water with a large tank. A garden mostly waters itself in normal years.
About 74 inches a year (PRISM, 1991 to 2020 average)
Wells
Shallow wells, so drilling should be one of the cheaper costs.
The typical well here is about 100 feet deep; a well typically runs $6,000 to $14,000
Growing season
A full season for most vegetables.
About 185 frost-free days, USDA zone 8b; last frost about April 17, first about October 25
Sun
Weak sun. Solar needs a generator behind it in winter.
About 3.6 hours of full sun a day, averaged over the year
Flood
Flood zones are rare here. Still, look up the parcel on FEMA's flood map.
FEMA maps no flood zones nearby
Wildfire
Moderate wildfire risk. Keep brush cleared around the house.
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: high
Terrain
Steep. A flat house site and a driveway route will drive the cost.
Slopes average about 26%, about 1,140 feet above sea level
Soil
Expect a costlier septic system, because the ground is steep. The county's soil test decides.
Silt 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 0.8 miles (OpenStreetMap)
Check a Washington 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
We found no public zoning map for Cowlitz 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.
Drilled to about 100 feet, with pump and pressure tank
Septic
$10,000 to $20,000
Mound, sand filter, or treatment unit
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
$37,000 to $78,000
Before the house
Before you make an offer on land here
Soil test
Get a soil test before you count on septic.
Steep ground can rule out a standard system.
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.
Road access
Confirm the parcel fronts a public road or has a recorded easement.
Without one, you may not have a legal way in.
Nearby counties
112,864 people live in Cowlitz County, about 98.9 per square mile. It ranks tied for 24th of the 39 Washington counties we scored, and Washington ranks 44th of 50 states.