Macon County, Missouri
The most common soil here is Armstrong, on about 15% of the land: a loam, a balanced mix that crumbles in your hand. Keswick and Winnegan come next.
About 2% of the land drains well, and 56% stays wet for long stretches; groundwater comes within two feet of the surface under 53% of it.
USDA rates 99% of the land very limited for a standard septic drain field, and 98% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 19% of the land floods occasionally or more, and bedrock lies within 40 inches under 1% 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 Macon 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 Moderately well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). 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 Macon 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 |
|---|---|---|---|---|---|
| Keswick clay loam, 9 to 20 percent slopes, severely eroded | 53K | Moderately well drained | D | Very limited | Very limited |
| Armstrong loam, 5 to 9 percent slopes, eroded | 34K | Somewhat poorly drained | D | Very limited | Very limited |
| Winnegan loam, 20 to 35 percent slopes | 30K | Moderately well drained | D | Very limited | Very limited |
| Winnegan loam, 14 to 20 percent slopes, eroded | 29K | Moderately well drained | D | Very limited | Very limited |
| Leonard silt loam, 1 to 6 percent slopes, eroded | 29K | Poorly drained | C/D | Very limited | Very limited |
| Armstrong loam, 9 to 14 percent slopes, eroded | 25K | Somewhat poorly drained | D | Very limited | Very limited |
| Adco silt loam, 1 to 3 percent slopes | 24K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Keswick clay loam, 5 to 9 percent slopes, eroded | 23K | Moderately well drained | D | Very limited | Very limited |
| Purdin loam, 14 to 20 percent slopes, eroded | 22K | Moderately well drained | D | Very limited | Very limited |
| Gorin silt loam, 3 to 9 percent slopes, eroded | 19K | Somewhat poorly drained | C | Very limited | Very limited |
| Armstrong clay loam, 9 to 14 percent slopes, severely eroded | 18K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Bevier silty clay loam, 3 to 8 percent slopes, moderately eroded | 16K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Adco silt loam, 1 to 3 percent slopes, eroded | 12K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Darwin silty clay, 0 to 2 percent slopes, occasionally flooded | 11K | Very poorly drained | D | Very limited | Very limited |
| Wilbur silt loam, 0 to 2 percent slopes, frequently flooded | 11K | Moderately well drained | B/D | Very limited | Very limited |
| Armstrong clay loam, 5 to 9 percent slopes, severely eroded | 9K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Chequest silty clay loam, 0 to 2 percent slopes, occasionally flooded | 9K | Poorly drained | D | Very limited | Very limited |
| Purdin clay loam, 20 to 35 percent slopes, eroded | 8K | Moderately well drained | D | Very limited | Very limited |
| Piopolis silty clay loam, 0 to 2 percent slopes, frequently flooded | 7K | Poorly drained | C/D | Very limited | Very limited |
| Tice silty clay loam, 0 to 2 percent slopes, frequently flooded, long duration | 7K | 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 98% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 99% 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.