Benton County, Oregon

Survey Area OR003• 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 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 Benton 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
Price-MacDunn-Ritner complex, 30 to 60 percent slopes	23K	Well drained	C	Very limited	Very limited
Jory-Gelderman complex, 12 to 30 percent slopes	20K	Well drained	C	Very limited	Very limited
Honeygrove-Peavine complex, 3 to 30 percent slopes	15K	Well drained	C	Somewhat limited	Very limited
Preacher-Bohannon-Slickrock complex, 35 to 60 percent slopes	15K	Well drained	B	Very limited	Very limited
Apt-McDuff complex, 5 to 30 percent slopes	13K	Well drained	C	Somewhat limited	Very limited
Dayton silt loam, 0 to 2 percent slopes	12K	Poorly drained	D	Very limited	Very limited
Dixonville-Gellatly complex, 12 to 30 percent slopes	11K	Well drained	D	Very limited	Very limited
Bohannon-Preacher complex, 30 to 60 percent slopes	11K	Well drained	C	Very limited	Very limited
Chehalis silty clay loam, 0 to 3 percent slopes	11K	Well drained	B	Very limited	Very limited
Waldo silty clay loam, 0 to 3 percent slopes	9K	Poorly drained	C/D	Very limited	Very limited
Digger-Remote-Umpcoos complex, 30 to 60 percent slopes	8K	Well drained	C	Very limited	Very limited
Woodburn silt loam, 0 to 3 percent slopes	8K	Moderately well drained	C	Very limited	Very limited
Jory silty clay loam, sedimentary bedrock, 12 to 20 percent slopes	8K	Well drained	C	Very limited	Very limited
Bellpine-Jory complex, 30 to 60 percent slopes	7K	Well drained	C	Very limited	Very limited
Apt-McDuff complex, 30 to 50 percent slopes	7K	Well drained	C	Very limited	Very limited
Preacher-Bohannon complex, 5 to 35 percent slopes	7K	Well drained	B	Somewhat limited	Somewhat limited
Bellpine-Jory complex, 12 to 20 percent slopes	6K	Well drained	C	Very limited	Very limited
Slickrock gravelly medial loam, 3 to 25 percent slopes	6K	Well drained	B	Somewhat limited	Somewhat limited
Honeygrove-Peavine complex, 30 to 60 percent slopes	6K	Well drained	C	Very limited	Very limited
Amity silt loam, 0 to 3 percent slopes	6K	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.

Mollisols

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

Ultisols

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

Alfisols

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

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

Andisols

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

What This Means

Building & Foundations

About 80% 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 93% 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.