Williamson County, Texas

Survey Area TX491• 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 Williamson 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	54K	Well drained	D	Very limited	Very limited
Eckrant stony clay, 0 to 3 percent slopes, stony	49K	Well drained	D	Very limited	Very limited
Houston Black clay, 1 to 3 percent slopes	43K	Moderately well drained	D	Very limited	Very limited
Branyon clay, 1 to 3 percent slopes	41K	Moderately well drained	D	Very limited	Very limited
Branyon clay, 0 to 1 percent slopes	40K	Moderately well drained	D	Very limited	Very limited
Doss silty clay, moist, 1 to 5 percent slopes	33K	Well drained	D	Very limited	Very limited
Georgetown stony clay loam, 1 to 3 percent slopes	31K	Well drained	D	Very limited	Very limited
Denton silty clay, 1 to 3 percent slopes	30K	Well drained	D	Very limited	Very limited
Fairlie clay, 1 to 2 percent slopes	27K	Moderately well drained	D	Very limited	Very limited
Austin silty clay, 1 to 3 percent slopes	26K	Well drained	D	Somewhat limited	Very limited
Eckrant-Rock outcrop association, 1 to 10 percent slopes	25K	Well drained	D	Very limited	Very limited
Ferris-Heiden complex, 5 to 15 percent slopes, moderately eroded	19K	Well drained	D	Very limited	Very limited
Austin-Whitewright complex, 2 to 6 percent slopes, eroded	19K	Well drained	D	Somewhat limited	Very limited
Burleson clay, 0 to 1 percent slopes	18K	Moderately well drained	D	Very limited	Very limited
Heiden clay, 2 to 5 percent slopes, moderately eroded	17K	Well drained	D	Very limited	Very limited
Tinn clay, 0 to 1 percent slopes, frequently flooded	16K	Moderately well drained	D	Very limited	Very limited
Brackett gravelly clay loam, 3 to 12 percent slopes	16K	Well drained	D	Very limited	Very limited
Castephen silty clay, 1 to 3 percent slopes	10K	Well drained	D	Very limited	Very limited
Branyon-Krum complex, 1 to 3 percent slopes	10K	Well drained	D	Very limited	Very limited
Heiden clay, 1 to 3 percent slopes	9K	Well drained	D	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.

Vertisols

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

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.

What This Means

Building & Foundations

About 91% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, 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.