Johnson County, Iowa

Survey Area IA103• 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 Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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 Johnson 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
Colo-Ely complex, 0 to 5 percent slopes	27K	Poorly drained	C/D	Very limited	Very limited
Tama silt loam, 2 to 5 percent slopes	20K	Well drained	C	Somewhat limited	Very limited
Fayette silt loam, till plain, 5 to 9 percent slopes, eroded	14K	Well drained	C	Somewhat limited	Very limited
Ladoga silt loam, 5 to 9 percent slopes, eroded	14K	Moderately well drained	C	Somewhat limited	Very limited
Ladoga silt loam, 9 to 14 percent slopes, eroded	13K	Moderately well drained	C	Somewhat limited	Very limited
Nodaway-Arenzville silt loams, 1 to 4 percent slopes	10K	Moderately well drained	B	Very limited	Very limited
Tama silt loam, 5 to 9 percent slopes, eroded	9K	Well drained	C	Somewhat limited	Very limited
Fayette silt loam, till plain, 14 to 18 percent slopes, eroded	9K	Well drained	C	Very limited	Very limited
Muscatine silt loam, 0 to 2 percent slopes	8K	Somewhat poorly drained	C/D	Very limited	Very limited
Fayette silty clay loam, till plain, 14 to 18 percent slopes, severely eroded	7K	Well drained	C	Very limited	Very limited
Fayette silt loam, till plain, 2 to 5 percent slopes	7K	Well drained	C	Somewhat limited	Very limited
Garwin silty clay loam, 0 to 2 percent slopes	7K	Poorly drained	C/D	Very limited	Very limited
Ladoga silt loam, 2 to 5 percent slopes	6K	Moderately well drained	C	Somewhat limited	Very limited
Clinton silt loam, 5 to 9 percent slopes, eroded	6K	Moderately well drained	C	Somewhat limited	Very limited
Fayette silt loam, till plain, 25 to 40 percent slopes	6K	Well drained	C	Very limited	Very limited
Water, lakes and reservoirs	6K			Not rated	Not rated
Clinton silt loam, 9 to 14 percent slopes, eroded	6K	Moderately well drained	C	Somewhat limited	Very limited
Colo silty clay loam, 0 to 2 percent slopes, ponded, occasionally flooded	6K	Poorly drained	C/D	Very limited	Very limited
Colo silt loam, 0 to 2 percent slopes, occasionally flooded, overwash	6K	Poorly drained	C/D	Very limited	Very limited
Sperry silt loam, depressional, 0 to 1 percent slopes	6K	Very poorly drained	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.

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 47% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 96% 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.