Iowa Soil Surveys

Iowa has 99 USDA soil survey areas covering a wide range of landscapes and soil conditions. The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter, making up roughly 48% of surveyed soils. Alfisols — moderately leached forest soils with a clay-enriched subsoil account for another 34%.

In terms of drainage, 36% of Iowa soils are classified as well drained. About 42% of soils have some form of poor drainage, which is important to consider for septic systems and foundations. Drainage class affects everything from septic system design to basement feasibility to garden planning. Use the survey area pages below to see drainage details for specific counties, or look up any address for an exact soil profile.