Umatilla County Area, Oregon

Survey Area OR667• Oregon

The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Umatilla County Area, Oregon. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map Unit	Acres	Drainage	Hydro Group	Dwellings	Septic
Walla Walla silt loam, 1 to 7 percent slopes	107K	Well drained	B	Not limited	Somewhat limited
Gwin-Rock outcrop complex, 40 to 70 percent slopes	93K	Well drained	D	Very limited	Very limited
Umatilla-Kahler-Gwin association, 35 to 70 percent slopes	72K	Well drained	B	Very limited	Very limited
Athena silt loam, 1 to 7 percent slopes	45K	Well drained	B	Not limited	Somewhat limited
Walla Walla silt loam, 7 to 12 percent slopes	38K	Well drained	B	Somewhat limited	Somewhat limited
Lickskillet very stony loam, 7 to 40 percent slopes	37K	Well drained	D	Very limited	Very limited
Ritzville silt loam, 2 to 7 percent slopes	34K	Well drained	B	Not limited	Somewhat limited
Albee-Bocker-Anatone complex, 2 to 15 percent slopes	32K	Well drained	D	Very limited	Very limited
Tolo silt loam, 3 to 15 percent slopes	31K	Well drained	C	Somewhat limited	Very limited
Pilot Rock silt loam, 1 to 7 percent slopes	31K	Well drained	C	Somewhat limited	Very limited
Buckcreek-Gwin association, 45 to 70 percent slopes	30K	Well drained	C	Very limited	Very limited
Gurdane-Rockly complex, 2 to 20 percent slopes	30K	Well drained	C	Very limited	Very limited
Klicker-Anatone-Bocker complex, 2 to 15 percent slopes	28K	Well drained	C	Very limited	Very limited
Shano silt loam, 2 to 7 percent slopes	26K	Well drained	B	Not limited	Somewhat limited
Morrow silt loam, 1 to 7 percent slopes	25K	Well drained	C	Very limited	Very limited
Ritzville silt loam, 12 to 25 percent slopes	23K	Well drained	B	Very limited	Very limited
Adkins fine sandy loam, 0 to 5 percent slopes	23K	Well drained	B	Not limited	Somewhat limited
Gurdane-Gwinly association, 20 to 40 percent slopes	22K	Well drained	C	Very limited	Very limited
Gwinly very cobbly silt loam, 7 to 40 percent slopes	21K	Well drained	D	Very limited	Very limited
Walla Walla silt loam, 12 to 25 percent north slopes	21K	Well drained	B	Very limited	Very limited

Soil Orders in This Area

The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Andisols

Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.

Aridisols

Dry-climate soils with low organic matter. Often have caliche layers that make excavation difficult. Low shrink-swell is good for foundations.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

What This Means

Building & Foundations

About 56% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.

Septic Systems

About 64% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.

Gardening & Agriculture

Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.