Jefferson County, Missouri
The most common soil here is Sonsac, on about 18% of the land: a very cobbly silt loam, smooth, like flour. Useful and Wrengart come next.
About 62% of the land drains well, and 4% stays wet for long stretches; groundwater comes within two feet of the surface under 5% of it.
USDA rates 94% of the land very limited for a standard septic drain field, and 74% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 13% of the land floods occasionally or more, and bedrock lies within 40 inches under 42% 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 Jefferson 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 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 Jefferson 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 |
|---|---|---|---|---|---|
| Sonsac gravelly silt loam, 15 to 40 percent slopes, very stony | 78K | Well drained | D | Very limited | Very limited |
| Useful silt loam, 15 to 40 percent slopes | 30K | Moderately well drained | D | Very limited | Very limited |
| Moko-Rock outcrop complex, 15 to 50 percent slopes, extremely stony | 25K | Well drained | D | Very limited | Very limited |
| Caneyville silt loam, 15 to 30 percent slopes | 24K | Well drained | C | Very limited | Very limited |
| Wrengart silt loam, 3 to 8 percent slopes, eroded | 18K | Moderately well drained | C | Somewhat limited | Very limited |
| Goss very cobbly silt loam, 15 to 50 percent slopes, extremely stony | 16K | Well drained | D | Very limited | Very limited |
| Useful silt loam, 8 to 15 percent slopes, eroded | 16K | Moderately well drained | D | Somewhat limited | Very limited |
| Useful silt loam, 3 to 8 percent slopes | 15K | Moderately well drained | C | Somewhat limited | Very limited |
| Gasconade-Rock outcrop complex, 15 to 50 percent slopes, rubbly | 14K | Somewhat excessively drained | D | Very limited | Very limited |
| Wrengart silt loam, 8 to 15 percent slopes, eroded | 12K | Moderately well drained | C | Somewhat limited | Very limited |
| Rueter gravelly silt loam, 15 to 55 percent slopes, extremely stony | 10K | Somewhat excessively drained | B | Very limited | Very limited |
| Rueter-Sonsac complex, 15 to 55 percent slopes, extremely stony | 8K | Somewhat excessively drained | D | Very limited | Very limited |
| Pevely-Holstein complex, 8 to 30 percent slopes | 8K | Moderately well drained | C | Very limited | Very limited |
| Haymond silt loam, 0 to 3 percent slopes, frequently flooded | 8K | Well drained | B | Very limited | Very limited |
| Bloomsdale silt loam, 0 to 3 percent slopes, frequently flooded | 8K | Well drained | C | Very limited | Very limited |
| Water | 7K | Subaqueous | Not rated | Not rated | |
| Weingarten silt loam, 15 to 50 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Minnith silt loam, 8 to 15 percent slopes, eroded | 6K | Moderately well drained | C | Somewhat limited | Very limited |
| Rueter gravelly silt loam, 3 to 15 percent slopes, very stony | 6K | Somewhat excessively drained | C | Somewhat limited | Very limited |
| Minnith silt loam, 3 to 8 percent slopes, eroded | 6K | Moderately well drained | C | Somewhat 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 74% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 94% 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.