Possible, but hard and costly. Only about 12 inches of rain falls a year, so you will rely on a well (near 510 feet here) or hauled water. Septic will likely cost more, because rock or a hard layer sits about 38 inches down.
What the land says
Rain
Desert rain. Plan on a well or hauled water, and on irrigating anything you grow.
About 12 inches a year (PRISM, 1991 to 2020 average)
Wells
Deep wells. Get a driller's quote before you offer.
The typical well here is about 510 feet deep; a well typically runs $25,000 to $54,000
Growing season
Enough for most vegetables. Start tomatoes and peppers indoors.
About 174 frost-free days, USDA zone 7b; last frost about April 26, first about October 22
Sun
Good sun. Size the array and battery bank for winter.
About 4.9 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
Low wildfire risk.
U.S. Forest Service wildfire hazard map: Very Low to 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
Terrain
Rolling ground. Look for a flat house site.
Slopes average about 11%, about 2,010 feet above sea level
Soil
Expect a costlier septic system, because rock or a hard layer sits about 38 inches down. 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 1.9 miles (OpenStreetMap)
Check an Oregon 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 Gilliam County, so call the county planning office with the parcel number to ask whether the land is zoned.
Building code
Oregon's building code applies uniformly statewide, including the Oregon Residential Specialty Code for houses (based on the International Residential Code), and cities and counties cannot set different requirements without state approval. City or county building departments issue house permits and inspect, and the state Building Codes Division does it for some counties.
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.