Audrain County, Missouri
The most common soil here is Mexico, on about 35% of the land: a silt loam, smooth, like flour. Leonard and Armstrong come next.
About under 1% of the land drains well, and 98% stays wet for long stretches; groundwater comes within two feet of the surface under 91% of it.
USDA rates 99% of the land very limited for a standard septic drain field, and 99% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 8% 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 Audrain 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 Poorly 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 Audrain 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 |
|---|---|---|---|---|---|
| Mexico silt loam, 1 to 4 percent slopes, eroded | 116K | Poorly drained | D | Very limited | Very limited |
| Leonard silt loam, 1 to 6 percent slopes, eroded | 72K | Poorly drained | C/D | Very limited | Very limited |
| Mexico silt loam, 0 to 2 percent slopes | 55K | Poorly drained | D | Very limited | Very limited |
| Armstrong loam, 5 to 9 percent slopes, eroded | 54K | Somewhat poorly drained | D | Very limited | Very limited |
| Putnam silt loam, 0 to 1 percent slopes | 53K | Poorly drained | D | Very limited | Very limited |
| Keswick silt loam, 5 to 9 percent slopes, eroded | 26K | Somewhat poorly drained | D | Very limited | Very limited |
| Belknap silt loam, 0 to 2 percent slopes, frequently flooded | 17K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Twomile silt loam, 0 to 2 percent slopes, occasionally flooded | 12K | Poorly drained | C/D | Very limited | Very limited |
| Gifford silt loam, 1 to 4 percent slopes | 5K | Poorly drained | D | Very limited | Very limited |
| Chariton silt loam, 0 to 2 percent slopes, rarely flooded | 4K | Poorly drained | C/D | Very limited | Very limited |
| Belknap silt loam, 1 to 3 percent slopes, frequently flooded | 4K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Marion silt loam, 2 to 5 percent slopes | 4K | Somewhat poorly drained | D | Very limited | Very limited |
| Keswick silt loam, 9 to 14 percent slopes, eroded | 4K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Twomile silt loam, 1 to 3 percent slopes, rarely flooded | 3K | Poorly drained | C/D | Very limited | Very limited |
| Winnegan loam, bedrock substratum, 9 to 14 percent slopes, eroded | 2K | Moderately well drained | D | Very limited | Very limited |
| Water | 2K | Subaqueous | Not rated | Not rated | |
| Armstrong clay loam, 5 to 9 percent slopes, severely eroded | 2K | Somewhat poorly drained | D | Very limited | Very limited |
| Winnegan silt loam, 14 to 30 percent slopes | 2K | Moderately well drained | D | Very limited | Very limited |
| Goss cobbly silt loam, 14 to 30 percent slopes | 1K | Well drained | C | Very limited | Very limited |
| Lenzburg clay loam, 5 to 50 percent slopes | 1K | Well drained | C | 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 99% 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. 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.