St. Louis County and St. Louis City, Missouri
The most common soil here is Harvester, on about 13% of the land: a silt loam, smooth, like flour. Menfro and Winfield come next.
About 28% of the land drains well, and 12% stays wet for long stretches; groundwater comes within two feet of the surface under 23% of it.
USDA rates 56% of the land very limited for a standard septic drain field, and 37% 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 3% 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 St. Louis County and St. Louis City, 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 C (slow infiltration, moderate 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 St. Louis County and St. Louis City, 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 |
|---|---|---|---|---|---|
| Urban land-Harvester complex, 2 to 9 percent slopes | 59K | Not rated | Not rated | ||
| Urban land-Harvester complex, 9 to 20 percent slopes | 34K | Not rated | Not rated | ||
| Menfro silt loam, 20 to 45 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Urban land-Harvester complex, karst, 2 to 9 percent slopes | 15K | Moderately well drained | C | Somewhat limited | Very limited |
| Fishpot-Urban land-Freeburg complex, 0 to 2 percent slopes, frequently flooded | 13K | Somewhat poorly drained | C | Very limited | Very limited |
| Water | 13K | Subaqueous | Not rated | Not rated | |
| Urban land, upland, 0 to 5 percent slopes | 13K | Not rated | Not rated | ||
| Gasconade-Rock outcrop complex, 15 to 50 percent slopes, rubbly | 10K | Somewhat excessively drained | D | Very limited | Very limited |
| Urban land-Vandeventer complex, 0 to 2 percent slopes | 10K | Not rated | Not rated | ||
| Goss very gravelly silt loam, 14 to 45 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Menfro silt loam, 9 to 14 percent slopes, eroded | 8K | Well drained | B | Somewhat limited | Somewhat limited |
| Urban land-Fishpot complex, 0 to 2 percent slopes, occasionally flooded | 8K | Not rated | Not rated | ||
| Menfro silt loam, 14 to 20 percent slopes, eroded | 8K | Well drained | C | Very limited | Very limited |
| Urban land-Harvester-Tower Grove complex, 3 to 8 percent slopes | 8K | Not rated | Not rated | ||
| Peers silty clay loam, 0 to 2 percent slopes, occasionally flooded | 8K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Haynie-Treloar-Blake complex, 0 to 2 percent slopes, frequently flooded | 8K | Well drained | B | Very limited | Very limited |
| Winfield-Urban land complex, 5 to 9 percent slopes | 7K | Moderately well drained | C | Somewhat limited | Very limited |
| Winfield silt loam, 9 to 14 percent slopes, eroded | 6K | Moderately well drained | C | Somewhat limited | Very limited |
| Menfro silt loam, 5 to 9 percent slopes, eroded | 6K | Well drained | C | Somewhat limited | Very limited |
| Fishpot-Urban land-Freeburg complex, 0 to 3 percent slopes | 6K | Somewhat poorly 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 37% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 56% 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.