Louisiana has 64 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 39% of surveyed soils. Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates account for another 18%.
In terms of drainage, 27% of Louisiana soils are classified as poorly drained. About 63% 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
39% of surveyed soils
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Ultisols
18% of surveyed soils
Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.
Vertisols
14% of surveyed soils
High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.
Inceptisols
12% of surveyed soils
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Entisols
10% of surveyed soils
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Histosols
3% of surveyed soils
Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.
Mollisols
1% of surveyed soils
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.