Wisconsin has 72 USDA soil survey areas covering a wide range of landscapes and soil conditions. The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil, making up roughly 46% of surveyed soils. Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter account for another 15%.
In terms of drainage, 38% of Wisconsin soils are classified as well drained. About 31% 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.
Alfisols
46% of surveyed soils
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Mollisols
15% of surveyed soils
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.
Spodosols
14% of surveyed soils
Acidic forest soils with a leached layer. Common under conifers. Often have drainage issues from a compacted subsoil layer.
Entisols
13% of surveyed soils
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Histosols
5% of surveyed soils
Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.
Inceptisols
4% of surveyed soils
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.