Mason County, Illinois
The dominant drainage class is Excessively drained and the dominant hydrologic group is A (high infiltration, low runoff). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. 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 Mason 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 |
|---|---|---|---|---|---|
| Plainfield sand, 1 to 7 percent slopes | 29K | Excessively drained | A | Not limited | Very limited |
| Bloomfield fine sand, 1 to 7 percent slopes | 20K | Somewhat excessively drained | A | Not limited | Very limited |
| Sparta loamy sand, Illinois till plain, 2 to 6 percent slopes | 19K | Excessively drained | A | Not limited | Very limited |
| Water | 17K | Not rated | Not rated | ||
| Onarga sandy loam, 0 to 2 percent slopes | 16K | Well drained | A | Not limited | Very limited |
| Marshan loam, 0 to 2 percent slopes | 14K | Poorly drained | B/D | Very limited | Very limited |
| Udolpho fine sandy loam, 0 to 2 percent slopes | 14K | Poorly drained | B/D | Very limited | Very limited |
| Ridgeville sandy loam, 0 to 2 percent slopes | 12K | Somewhat poorly drained | A/D | Very limited | Very limited |
| Plainfield sand, 7 to 15 percent slopes | 12K | Excessively drained | A | Somewhat limited | Very limited |
| Ade loamy fine sand, 1 to 6 percent slopes | 12K | Somewhat excessively drained | A | Not limited | Very limited |
| Dakota fine sandy loam, 0 to 2 percent slopes | 11K | Well drained | B | Not limited | Very limited |
| Disco sandy loam, 0 to 2 percent slopes | 10K | Well drained | A | Not limited | Very limited |
| Dockery silt loam, 0 to 2 percent slopes, frequently flooded, long duration | 10K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Selma loam, 0 to 2 percent slopes | 9K | Poorly drained | B/D | Very limited | Very limited |
| Edgington silt loam, 0 to 2 percent slopes | 8K | Poorly drained | C/D | Very limited | Very limited |
| Onarga sandy loam, 2 to 5 percent slopes | 7K | Well drained | A | Not limited | Very limited |
| Gilford fine sandy loam, 0 to 2 percent slopes | 7K | Poorly drained | A/D | Very limited | Very limited |
| Harpster silty clay loam, 0 to 2 percent slopes | 7K | Poorly drained | B/D | Very limited | Very limited |
| Broadwell silt loam, 2 to 5 percent slopes | 7K | Well drained | B | Somewhat limited | Very limited |
| Tama silt loam, 2 to 5 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat 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 32% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 90% of soils are rated "very limited" for septic absorption fields. The well-drained soils may actually drain too fast for standard leach fields, allowing effluent to reach groundwater. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Soils tend to drain very quickly, meaning nutrients and water don't stick around long. Raised beds with amended soil, drip irrigation, and heavy mulching will give the best results. Compost is your best friend here — it improves water retention dramatically.