San Juan County, Washington

Survey Area WA055• Washington

The dominant drainage class is Well drained and the dominant hydrologic group is C/D (varies with drainage). 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 San Juan County, 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
Cady-Rock Outcrop complex, 5 to 30 percent slopes	11K	Well drained	D	Very limited	Very limited
Doebay-Cady-Rock Outcrop complex, 10 to 30 percent slopes	11K	Well drained	C	Very limited	Very limited
Cady-Doebay-Rock Outcrop complex, 25 to 75 percent slopes	7K	Well drained	D	Very limited	Very limited
Coveland loam, 0 to 5 percent slopes	6K	Somewhat poorly drained	C/D	Very limited	Very limited
Roche-Killebrew-Rock Outcrop complex, 5 to 35 percent slopes	5K	Moderately well drained	C/D	Very limited	Very limited
Roche-Killebrew complex, 2 to 10 percent slopes	4K	Moderately well drained	C/D	Very limited	Very limited
Doebay, moist-Cady-Rock Outcrop complex, 10 to 30 percent slopes	4K	Well drained	C	Very limited	Very limited
Mitchellbay gravelly sandy loam, 5 to 15 percent slopes	4K	Somewhat poorly drained	C/D	Very limited	Very limited
Mitchellbay gravelly sandy loam, 0 to 5 percent slopes	4K	Somewhat poorly drained	C/D	Very limited	Very limited
Pickett-Kahboo-Rock Outcrop complex, 25 to 75 percent slopes	4K	Well drained	B	Very limited	Very limited
Haro-Hiddenridge-Rock Outcrop complex, 5 to 30 percent slopes	3K	Well drained	D	Very limited	Very limited
Doebay-Morancreek complex, 5 to 25 percent slopes	3K	Well drained	C	Very limited	Very limited
Mitchellbay-Sholander-Bazal complex, 0 to 8 percent slopes	3K	Somewhat poorly drained	C/D	Very limited	Very limited
Coveland-Mitchellbay complex, 2 to 15 percent slopes	3K	Somewhat poorly drained	C/D	Very limited	Very limited
Turtleback-Cady-Rock Outcrop complex, 25 to 75 percent slopes	2K	Well drained	A	Very limited	Very limited
Everett sandy loam, warm, 3 to 20 percent slopes	2K	Somewhat excessively drained	A	Somewhat limited	Very limited
Whidbey-Hoypus complex, 2 to 15 percent slopes	2K	Moderately well drained	B/D	Very limited	Very limited
Beaches-Endoaquents, tidal-Xerorthents association, 0 to 5 percent slopes	2K			Very limited	Very limited
Mitchellbay-Rock Outcrop-Killebrew complex, 3 to 15 percent slopes	2K	Somewhat poorly drained	C/D	Very limited	Very limited
Deadmanbay-Morancreek complex, 2 to 15 percent slopes	2K	Somewhat poorly drained	C/D	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.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

Mollisols

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

Entisols

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

What This Means

Building & Foundations

About 97% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.

Septic Systems

About 100% 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.