Tripp County, South Dakota

Survey Area SD123• South Dakota

The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high 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 Tripp County, South Dakota. 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
Millboro silty clay, 3 to 6 percent slopes	98K	Well drained	D	Very limited	Very limited
Millboro silty clay, 0 to 3 percent slopes	57K	Well drained	D	Very limited	Very limited
Lakoma-Millboro silty clays, 6 to 9 percent slopes	57K	Well drained	D	Very limited	Very limited
Doger loamy fine sand, 0 to 6 percent slopes	45K	Well drained	A	Not limited	Very limited
Lakoma-Okaton silty clays, 6 to 15 percent slopes	44K	Well drained	D	Very limited	Very limited
Sansarc-Opal clays, 9 to 25 percent slopes	41K	Well drained	D	Very limited	Very limited
Valentine-Dunday complex, 3 to 9 percent slopes	32K	Excessively drained	A	Not limited	Very limited
Reliance silty clay loam, 3 to 6 percent slopes	26K	Well drained	C	Somewhat limited	Very limited
Anselmo-Longpine fine sandy loams, 10 to 20 percent slopes	25K	Well drained	A	Somewhat limited	Very limited
Boro-Millboro silty clays, 6 to 9 percent slopes	24K	Well drained	D	Very limited	Very limited
Okaton-Lakoma silty clays, 15 to 40 percent slopes	22K	Well drained	D	Very limited	Very limited
Witten silty clay, 0 to 3 percent slopes	21K	Moderately well drained	C	Very limited	Very limited
Boyd-Okaton association, 9 to 25 percent slopes	20K	Well drained	D	Very limited	Very limited
Dunday-Doger loamy fine sands, 3 to 9 percent slopes	19K	Somewhat excessively drained	A	Not limited	Very limited
Dunday loamy fine sand, 3 to 9 percent slopes, eroded	18K	Somewhat excessively drained	A	Not limited	Very limited
Anselmo-Vetal fine sandy loams, 0 to 3 percent slopes	18K	Well drained	A	Not limited	Very limited
Reliance silty clay loam, 0 to 3 percent slopes	17K	Well drained	C	Somewhat limited	Very limited
Millboro silty clay, 6 to 9 percent slopes	16K	Well drained	D	Very limited	Very limited
Anselmo fine sandy loam, 3 to 6 percent slopes	16K	Well drained	A	Not limited	Very limited
Anselmo-Holt fine sandy loams, 3 to 9 percent slopes	14K	Well 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.

Vertisols

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

Entisols

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

What This Means

Building & Foundations

About 63% 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 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.