Callahan County, Texas
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). 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 Callahan County, Texas.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Throck-Speck association, undulating | 64K | Well drained | D | Very limited | Very limited |
| Throck-Owens-Lueders association, hilly | 50K | Well drained | D | Very limited | Very limited |
| Lueders-Speck association, undulating | 49K | Well drained | D | Very limited | Very limited |
| Throck-Callahan-Owens association, undulating | 33K | Well drained | D | Very limited | Very limited |
| Chaney loamy fine sand, 0 to 3 percent slopes | 33K | Moderately well drained | C | Somewhat limited | Very limited |
| Leeray clay, 1 to 3 percent slopes | 30K | Well drained | D | Very limited | Very limited |
| Pedernales fine sandy loam, 1 to 3 percent slopes | 25K | Well drained | C | Somewhat limited | Very limited |
| Frio-Gageby association, frequently flooded | 25K | Well drained | C | Very limited | Very limited |
| Speck-Throck association, gently undulating | 24K | Well drained | D | Very limited | Very limited |
| Sagerton loam, 1 to 3 percent slopes | 22K | Well drained | C | Somewhat limited | Very limited |
| Cisco-Hext-Pedernales association, undulating | 20K | Well drained | C | Somewhat limited | Very limited |
| Pedernales fine sandy loam, 1 to 5 percent slopes, moderately eroded | 14K | Well drained | C | Somewhat limited | Very limited |
| Rowden clay loam, 0 to 3 percent slopes | 13K | Well drained | D | Very limited | Very limited |
| Hext-Oplin-Brackett association, hilly | 13K | Well drained | D | Very limited | Very limited |
| Pedernales loamy fine sand, 1 to 5 percent slopes | 12K | Well drained | C | Somewhat limited | Very limited |
| Cisco-Hext-Pedernales complex, 1 to 5 percent slopes | 12K | Well drained | C | Somewhat limited | Very limited |
| Nukrum clay, 1 to 3 percent slopes | 12K | Well drained | C | Very limited | Very limited |
| Demona-Patilo complex, 1 to 5 percent slopes | 11K | Moderately well drained | A | Very limited | Very limited |
| Owens-Throck association, hilly | 10K | Well drained | D | Very limited | Very limited |
| Frio clay loam, occasionally flooded | 9K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 71% 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 100% 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
Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.