Callahan County, Texas

Survey Area TX059• Texas

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 Callahan 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
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

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.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

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.