Walla Walla County Area, Washington

Survey Area WA671• Washington

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 Walla Walla County Area, Washington. 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
Ritzville silt loam, 8 to 30 percent slopes	131K	Well drained	B	Very limited	Very limited
Walla Walla silt loam, 8 to 30 percent slopes	74K	Well drained	B	Very limited	Very limited
Ritzville silt loam, 30 to 45 percent slopes	35K	Well drained	B	Very limited	Very limited
Ritzville silt loam, 0 to 8 percent slopes	33K	Well drained	B	Not limited	Somewhat limited
Walla Walla silt loam, 30 to 45 percent slopes	28K	Well drained	B	Very limited	Very limited
Ritzville very fine sandy loam, 0 to 8 percent slopes	28K	Well drained	B	Not limited	Somewhat limited
Athena silt loam, 8 to 30 percent slopes	25K	Well drained	B	Very limited	Very limited
Ritzville very fine sandy loam, 8 to 30 percent slopes	24K	Well drained	B	Very limited	Very limited
Walla Walla silt loam, 0 to 8 percent slopes	21K	Well drained	B	Not limited	Somewhat limited
Water	18K			Not rated	Not rated
Adkins loamy fine sand, 0 to 15 percent slopes	18K	Well drained	B	Not limited	Somewhat limited
Basalt rockland, steep	17K			Very limited	Very limited
Quincy fine sand, 0 to 30 percent slopes, eroded	16K	Excessively drained	A	Very limited	Very limited
Adkins fine sandy loam, 0 to 15 percent slopes	14K	Well drained	B	Not limited	Somewhat limited
Palouse silt loam, 8 to 30 percent slopes, eroded	12K	Well drained	B	Very limited	Very limited
Onyx silt loam, 0 to 3 percent slopes	11K	Well drained	B	Very limited	Very limited
Gwin rocky silt loam, 30 to 60 percent slopes	8K	Well drained	D	Very limited	Very limited
Ellisforde silt loam, 15 to 30 percent slopes	8K	Well drained	C	Very limited	Very limited
Hezel loamy fine sand, 0 to 15 percent slopes, eroded	7K	Somewhat excessively drained	C	Not limited	Very limited
Quincy loamy fine sand, 0 to 8 percent slopes, eroded	7K	Excessively drained	A	Not 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.

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.

Andisols

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

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

What This Means

Building & Foundations

About 72% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 75% 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.