Logan County, Illinois
The most common soil here is Sable, on about 18% of the land: a silty clay loam, smooth and slightly sticky. Ipava and Tama come next.
About 30% of the land drains well, and 62% stays wet for long stretches; groundwater comes within two feet of the surface under 62% of it.
USDA rates 87% of the land very limited for a standard septic drain field, and 64% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 10% 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 soils you're most likely standing on
The biggest named soils in Logan County, Illinois, each drawn five feet deep from its official USDA description, in its recorded colors.
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 Poorly drained and the dominant hydrologic group is B/D (varies with drainage). 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 Logan County, Illinois. 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 |
|---|---|---|---|---|---|
| Sable silty clay loam, 0 to 2 percent slopes | 79K | Poorly drained | B/D | Very limited | Very limited |
| Ipava silt loam, 0 to 2 percent slopes | 78K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Osco silt loam, 2 to 5 percent slopes | 17K | Well drained | B | Somewhat limited | Somewhat limited |
| Sawmill silty clay loam, 0 to 2 percent slopes, frequently flooded | 15K | Poorly drained | B/D | Very limited | Very limited |
| Plano silt loam, 0 to 2 percent slopes | 10K | Well drained | B | Somewhat limited | Very limited |
| Tama silt loam, very deep to sand, 2 to 5 percent slopes | 9K | Well drained | B | Somewhat limited | Very limited |
| Hartsburg silty clay loam, 0 to 2 percent slopes | 9K | Poorly drained | B/D | Very limited | Very limited |
| Buckhart silt loam, 0 to 2 percent slopes | 9K | Moderately well drained | C | Somewhat limited | Very limited |
| Buckhart silt loam, 2 to 5 percent slopes | 8K | Moderately well drained | C | Somewhat limited | Very limited |
| Knight silt loam, 0 to 2 percent slopes | 6K | Poorly drained | C/D | Very limited | Very limited |
| Plano silt loam, sandy substratum, 2 to 5 percent slopes | 6K | Well drained | B | Somewhat limited | Very limited |
| Tama silt loam, 2 to 5 percent slopes | 6K | Well drained | B | Somewhat limited | Somewhat limited |
| Rozetta silt loam, 2 to 5 percent slopes | 6K | Well drained | B | Somewhat limited | Somewhat limited |
| Broadwell silt loam, 2 to 5 percent slopes | 6K | Well drained | B | Somewhat limited | Very limited |
| Tama silt loam, very deep to sand, 0 to 2 percent slopes | 5K | Well drained | B | Somewhat limited | Very limited |
| Elburn silt loam, 0 to 2 percent slopes | 5K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Keomah silt loam, 0 to 2 percent slopes | 5K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Lawson silt loam, cool mesic, 0 to 2 percent slopes, frequently flooded | 5K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Drummer silty clay loam, 0 to 2 percent slopes | 4K | Poorly drained | B/D | Very limited | Very limited |
| Tice silty clay loam, sandy substratum, 0 to 2 percent slopes, frequently flooded | 4K | Somewhat poorly drained | B/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.
What This Means
Building & Foundations
About 64% of soils are rated "very limited" for dwellings with basements. Specific challenges include poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 87% of soils are rated "very limited" for septic absorption fields. Poorly drained soils can't absorb septic effluent effectively. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Many soils hold water for extended periods. Raised beds are highly recommended to improve drainage for vegetables. Well-adapted native plants and water-loving species will do best in natural conditions.