Bexar County, Texas
The most common soil here is Eckrant, on about 14% of the land: a very cobbly clay, sticky when wet and rock-hard when dry. Houston Black and Lewisville come next.
About 78% of the land drains well.
USDA rates 94% of the land very limited for a standard septic drain field, and 73% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 6% of the land floods occasionally or more, and bedrock lies within 40 inches under 33% 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 Bexar County, Texas, 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 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 Bexar County, Texas. 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 |
|---|---|---|---|---|---|
| Eckrant cobbly clay, 1 to 8 percent slopes | 63K | Well drained | D | Very limited | Very limited |
| Lewisville silty clay, 0 to 1 percent slopes | 42K | Well drained | C | Very limited | Very limited |
| Aluf sand, 0 to 5 percent slopes | 42K | Somewhat excessively drained | A | Not limited | Very limited |
| Branyon clay, 0 to 1 percent slopes | 34K | Moderately well drained | D | Very limited | Very limited |
| Eckrant-Rock outcrop association, 8 to 30 percent slopes | 34K | Well drained | D | Very limited | Very limited |
| Eckrant very cobbly clay, 5 to 15 percent slopes | 34K | Well drained | D | Very limited | Very limited |
| Lewisville silty clay, 1 to 3 percent slopes | 32K | Well drained | C | Very limited | Very limited |
| Crawford, stony and Bexar soils, 0 to 5 percent slopes | 30K | Well drained | D | Very limited | Very limited |
| Houston Black clay, 1 to 3 percent slopes | 29K | Moderately well drained | D | Very limited | Very limited |
| Wilco loamy fine sand, 0 to 3 percent slopes | 28K | Well drained | C | Somewhat limited | Very limited |
| Houston Black gravelly clay, 1 to 3 percent slopes | 27K | Moderately well drained | D | Very limited | Very limited |
| Brackett gravelly clay loam, 12 to 20 percent slopes | 24K | Well drained | D | Very limited | Very limited |
| Houston Black gravelly clay, 3 to 5 percent slopes | 21K | Moderately well drained | D | Very limited | Very limited |
| Tinn and Frio soils, 0 to 1 percent slopes, frequently flooded | 20K | Moderately well drained | D | Very limited | Very limited |
| Miguel fine sandy loam, 1 to 3 percent slopes | 20K | Well drained | C | Somewhat limited | Very limited |
| Brackett-Eckrant association, 20 to 60 percent slopes | 17K | Well drained | D | Very limited | Very limited |
| San Antonio clay loam, 1 to 3 percent slopes | 17K | Well drained | C | Very limited | Very limited |
| Krum clay, 1 to 5 percent slopes | 14K | Well drained | C | Very limited | Very limited |
| Patrick soils, 1 to 3 percent slopes, rarely flooded | 14K | Well drained | B | Very limited | Very limited |
| Sunev clay loam, 1 to 3 percent slopes | 13K | Well drained | B | Not limited | Somewhat 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 73% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, 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.