Buchanan County, Missouri
The most common soil here is Knox, on about 21% of the land: a silt loam, smooth, like flour. Marshall and Colo come next.
About 51% of the land drains well, and 32% stays wet for long stretches; groundwater comes within two feet of the surface under 27% of it.
USDA rates 58% of the land very limited for a standard septic drain field, and 60% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 18% of the land floods occasionally or more, and bedrock lies within 40 inches under 5% of it.
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 Buchanan County, Missouri, 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 Well drained and the dominant hydrologic group is B (moderate infiltration). 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 Buchanan County, Missouri. 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 |
|---|---|---|---|---|---|
| Marshall silt loam, 9 to 14 percent slopes, eroded | 20K | Well drained | B | Somewhat limited | Somewhat limited |
| Knox silt loam, 9 to 14 percent slopes, eroded | 18K | Well drained | B | Somewhat limited | Somewhat limited |
| Contrary silt loam, 9 to 14 percent slopes | 16K | Well drained | B | Somewhat limited | Somewhat limited |
| Marshall silt loam, 5 to 9 percent slopes, eroded | 16K | Well drained | B | Somewhat limited | Somewhat limited |
| Knox silty clay loam, 14 to 20 percent slopes, severely eroded | 16K | Well drained | B | Very limited | Very limited |
| Colo silt loam, 1 to 4 percent slopes, occasionally flooded | 14K | Poorly drained | C/D | Very limited | Very limited |
| Lamoni silty clay loam, 9 to 14 percent slopes, moderately eroded | 14K | Somewhat poorly drained | D | Very limited | Very limited |
| Colo silty clay loam, heavy till, 0 to 2 percent slopes, occasionally flooded | 12K | Poorly drained | C/D | Very limited | Very limited |
| Haynie silt loam, 0 to 2 percent slopes, rarely flooded | 12K | Moderately well drained | B | Very limited | Somewhat limited |
| Onawa silty clay, 0 to 2 percent slopes, rarely flooded | 9K | Somewhat poorly drained | D | Very limited | Very limited |
| Knox silt loam, 5 to 9 percent slopes, eroded | 8K | Well drained | B | Somewhat limited | Somewhat limited |
| Higginsville silty clay loam, 9 to 14 percent slopes, eroded | 7K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Gasconade flaggy silty clay loam, 14 to 35 percent slopes | 5K | Somewhat excessively drained | D | Very limited | Very limited |
| Gosport silty clay loam, 15 to 45 percent slopes | 5K | Moderately well drained | D | Very limited | Very limited |
| Knox silt loam, 20 to 35 percent slopes | 5K | Well drained | B | Very limited | Very limited |
| Waldron silty clay loam, 0 to 2 percent slopes, rarely flooded | 4K | Somewhat poorly drained | D | Very limited | Very limited |
| Sharpsburg silt loam, 5 to 9 percent slopes, eroded | 4K | Moderately well drained | C | Very limited | Very limited |
| Water | 4K | Subaqueous | Not rated | Not rated | |
| Gosport-Gasconade complex, 20 to 45 percent slopes | 3K | Moderately well drained | D | Very limited | Very limited |
| Urban land, bottomland, 0 to 3 percent slopes, rarely flooded | 3K | Not rated | Not rated |
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 60% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 58% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.