Soil survey area

Scott County, Iowa

Survey Area IA163• Iowa
The short version

The most common soil here is Tama, on about 27% of the land: a silty clay loam, smooth and slightly sticky. Muscatine and Downs come next.

About 56% of the land drains well, and 31% stays wet for long stretches; groundwater comes within two feet of the surface under 31% of it.

USDA rates 93% of the land very limited for a standard septic drain field, and 42% very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: 14% of the land floods occasionally or more.

Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.

The ground underfoot

The soils you're most likely standing on

The biggest named soils in Scott County, Iowa, each drawn five feet deep from its official USDA description, in its recorded colors.

Tama
27% of the area
Silty clay loam topsoil · well drained
Smooth and slightly sticky. Holds a lot of water.
Mollisols
Muscatine
9% of the area
Silty clay loam topsoil · somewhat poorly drained
Smooth and slightly sticky. Holds a lot of water.
Mollisols
Downs
9% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Alfisols
Fayette
5% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Alfisols
Colo
4% of the area
Silty clay loam topsoil · poorly drained
Smooth and slightly sticky. Holds a lot of water.
Mollisols
Garwin
4% of the area
Silty clay loam topsoil · poorly drained
Smooth and slightly sticky. Holds a lot of water.
Mollisols

Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.

The biggest mapped areas

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 Scott County, Iowa. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
Tama silty clay loam, 2 to 5 percent slopes 40K Well drainedCSomewhat limitedVery limited
Tama silty clay loam, 5 to 9 percent slopes, eroded 27K Well drainedCSomewhat limitedVery limited
Muscatine silty clay loam, 0 to 2 percent slopes 24K Somewhat poorly drainedC/DVery limitedVery limited
Garwin silty clay loam, 0 to 2 percent slopes 11K Poorly drainedC/DVery limitedVery limited
Colo silty clay loam, 0 to 2 percent slopes, occasionally flooded 9K Poorly drainedC/DVery limitedVery limited
Downs-Urban land complex, 2 to 9 percent slopes 8K Well drainedCSomewhat limitedVery limited
Downs silt loam, till plain, 5 to 9 percent slopes, eroded 7K Well drainedCSomewhat limitedVery limited
Water 7K Not ratedNot rated
Ambraw-Perks-Lawson complex, frequently flooded, 0 to 2 percent slopes 6K Poorly drainedC/DVery limitedVery limited
Colo-Ely complex, 0 to 5 percent slopes 6K Poorly drainedC/DVery limitedVery limited
Tama silty clay loam, 9 to 14 percent slopes, eroded 6K Well drainedCSomewhat limitedVery limited
Ackmore silt loam, 0 to 2 percent slopes, occasionally flooded 5K Somewhat poorly drainedC/DVery limitedVery limited
Urban land 5K Not ratedNot rated
Downs silt loam, till plain, 9 to 14 percent slopes, eroded 5K Well drainedCSomewhat limitedVery limited
Dockery silt loam, 2 to 5 percent slopes 5K Somewhat poorly drainedB/DVery limitedVery limited
Downs silt loam, till plain, 2 to 5 percent slopes 4K Well drainedCSomewhat limitedVery limited
Killduff silty clay loam, 9 to 14 percent slopes, severely eroded 4K Moderately well drainedCSomewhat limitedSomewhat limited
Fayette silt loam, till plain, 5 to 9 percent slopes, eroded 4K Well drainedCSomewhat limitedVery limited
Tama silty clay loam, 5 to 9 percent slopes 3K Well drainedCSomewhat limitedVery limited
Killduff silty clay loam, 5 to 9 percent slopes, eroded 3K Moderately well drainedCSomewhat limitedVery 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.
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 42% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

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

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.

Look Up a Specific Address

📍