Sioux County, Iowa

Survey Area IA167• Iowa

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 Sioux County, Iowa. 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
Galva silty clay loam, 2 to 5 percent slopes, eroded	109K	Well drained	C	Somewhat limited	Very limited
Galva silty clay loam, 2 to 5 percent slopes	71K	Well drained	C	Somewhat limited	Very limited
Primghar silty clay loam, 0 to 2 percent slopes	41K	Somewhat poorly drained	C/D	Very limited	Very limited
Galva silty clay loam, 5 to 9 percent slopes, eroded	34K	Well drained	C	Somewhat limited	Very limited
Primghar silty clay loam, 2 to 5 percent slopes	26K	Somewhat poorly drained	C/D	Very limited	Very limited
Colo silty clay loam, deep loess, 0 to 2 percent slopes, occasionally flooded	20K	Poorly drained	C/D	Very limited	Very limited
Galva silty clay loam, 0 to 2 percent slopes	19K	Well drained	C	Somewhat limited	Very limited
Radford silt loam, 0 to 2 percent slopes	15K	Somewhat poorly drained	C/D	Very limited	Very limited
Marcus silty clay loam, 0 to 2 percent slopes	13K	Poorly drained	C/D	Very limited	Very limited
Galva silty clay loam, terrace, 0 to 2 percent slopes	11K	Well drained	C	Somewhat limited	Very limited
Radford-Judson complex, 0 to 5 percent slopes	10K	Somewhat poorly drained	C/D	Very limited	Very limited
Moody silty clay loam, cool, 2 to 6 percent slopes, eroded	9K	Well drained	C	Somewhat limited	Very limited
Afton silty clay loam, 0 to 2 percent slopes, occasionally flooded	8K	Poorly drained	C/D	Very limited	Very limited
Judson silty clay loam, deep loess, 2 to 5 percent slopes	7K	Well drained	C	Somewhat limited	Very limited
Galva silty clay loam, terrace, 2 to 5 percent slopes	7K	Well drained	C	Somewhat limited	Very limited
Ely silty clay loam, shallow loess, 2 to 5 percent slopes	6K	Somewhat poorly drained	C/D	Very limited	Very limited
Moody silty clay loam, cool, 6 to 11 percent slopes, eroded	6K	Well drained	C	Somewhat limited	Very limited
Ida silt loam, 5 to 9 percent slopes, severely eroded	5K	Well drained	B	Not limited	Somewhat limited
Calco silty clay loam, 0 to 2 percent slopes, occasionally flooded	4K	Poorly drained	C/D	Very limited	Very limited
Wadena loam, 32 to 40 inches to sand and gravel, 0 to 2 percent	4K	Well drained	B	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.

Inceptisols

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

Entisols

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

What This Means

Building & Foundations

About 33% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 98% 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

Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.