Jefferson County Area, Washington

Survey Area WA631• Washington

The dominant drainage class is Moderately well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols. 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 Jefferson 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
Dimal very flaggy silty clay loam, 50 to 90 percent slopes	49K	Somewhat excessively drained	D	Very limited	Very limited
Solleks channery silty clay loam, 30 to 50 percent slopes	32K	Well drained	B	Very limited	Very limited
Hoko gravelly silt loam, 0 to 15 percent slopes	25K	Moderately well drained	C	Very limited	Very limited
Hoko-Snahopish association, hilly	17K	Moderately well drained	C	Very limited	Very limited
Alderwood gravelly sandy loam, 0 to 15 percent slopes	16K	Moderately well drained	B	Very limited	Very limited
Skookumcreek-Bonjonpass-Mountscott complex, 0 to 100 percent slopes	15K	Well drained	A	Very limited	Very limited
Klone-Hoko association, moderately steep	15K	Well drained	B	Very limited	Very limited
Sinclair gravelly sandy loam, 0 to 15 percent slopes	13K	Moderately well drained	B	Very limited	Very limited
Calawah silt loam, 0 to 8 percent slopes	12K	Moderately well drained	B	Not limited	Somewhat limited
Mountdeception-Irely complex, 35 to 100 percent slopes	11K	Well drained	A	Very limited	Very limited
Willapa-Calawah complex, 15 to 45 percent slopes	9K	Moderately well drained	B/D	Very limited	Very limited
Clallam gravelly sandy loam, 0 to 15 percent slopes	9K	Well drained	D	Very limited	Very limited
Alderwood gravelly sandy loam, 15 to 30 percent slopes	7K	Moderately well drained	B	Very limited	Very limited
Snahopish silty clay loam, 0 to 30 percent slopes	6K	Well drained	B	Very limited	Very limited
Alderwood gravelly loam, 0 to 15 percent slopes	6K	Moderately well drained	B	Very limited	Very limited
Sinclair gravelly sandy loam, 15 to 30 percent slopes	6K	Moderately well drained	B	Very limited	Very limited
Jolleycreek-Saghalie complex, 0 to 60 percent slopes	6K	Well drained	A	Very limited	Very limited
Itswoot very cobbly silt loam, 0 to 30 percent slopes	5K	Well drained	C	Very limited	Very limited
Hoko-Tealwhit association, gently rolling	5K	Moderately well drained	C	Very limited	Very limited
Dabob very gravelly sandy loam, 0 to 15 percent slopes	5K	Moderately 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.

Inceptisols

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

Andisols

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

Entisols

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

Spodosols

Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.

What This Means

Building & Foundations

About 95% 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 95% 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.