Polk County, Oregon

Survey Area OR053• Oregon

The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates. 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 Polk County, 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
Kilchis-Klickitat complex, 60 to 90 percent slopes	22K	Well drained	D	Very limited	Very limited
Woodburn silt loam, 0 to 3 percent slopes	16K	Moderately well drained	C	Very limited	Very limited
Bohannon gravelly loam, 50 to 75 percent slopes	15K	Well drained	B	Very limited	Very limited
Valsetz-Yellowstone complex, 50 to 90 percent slopes	14K	Well drained	B	Very limited	Very limited
Waldo silty clay loam	14K	Poorly drained	C/D	Very limited	Very limited
Dayton silt loam	13K	Poorly drained	D	Very limited	Very limited
Jory silty clay loam, 12 to 20 percent slopes	13K	Well drained	C	Very limited	Very limited
Valsetz stony loam, 50 to 75 percent slopes	11K	Well drained	B	Very limited	Very limited
Amity silt loam	11K	Somewhat poorly drained	C/D	Very limited	Very limited
Klickitat gravelly clay loam, 50 to 75 percent slopes	10K	Well drained	B	Very limited	Very limited
Jory silty clay loam, 20 to 30 percent slopes	9K	Well drained	C	Very limited	Very limited
Woodburn silt loam, 3 to 12 percent slopes	9K	Moderately well drained	C	Very limited	Very limited
Blachly silty clay loam, 3 to 30 percent slopes	9K	Well drained	C	Very limited	Very limited
Honeygrove silty clay loam, 3 to 25 percent slopes	8K	Well drained	C	Somewhat limited	Very limited
Bellpine silty clay loam, 3 to 12 percent slopes	7K	Well drained	C	Somewhat limited	Very limited
Helmick silt loam, 3 to 12 percent slopes	7K	Somewhat poorly drained	D	Very limited	Very limited
Valsetz stony loam, 3 to 30 percent slopes	7K	Well drained	B	Very limited	Very limited
Astoria silt loam, 5 to 30 percent slopes	7K	Well drained	B	Very limited	Very limited
Astoria silt loam, 30 to 60 percent slopes	7K	Well drained	B	Very limited	Very limited
Jory silty clay loam, 2 to 12 percent slopes	6K	Well drained	C	Somewhat 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.

Ultisols

Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.

Mollisols

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

Alfisols

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

Inceptisols

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

What This Means

Building & Foundations

About 89% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, 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.