King County, Texas
The most common soil here is Talpa, on about 12% of the land: a gravelly loam, a balanced mix that crumbles in your hand. Cottonwood and Knoco come next.
About 96% of the land drains well.
USDA rates 81% of the land very limited for a standard septic drain field, and 55% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 3% of the land floods occasionally or more, and bedrock lies within 40 inches under 65% 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 King 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 Inceptisols — young soils with minimal horizon development but more than Entisols. 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 King 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 |
|---|---|---|---|---|---|
| Cottonwood-Knoco complex, 3 to 20 percent slopes | 78K | Well drained | D | Very limited | Very limited |
| Talpa-Knoco-Rock outcrop complex, 5 to 30 percent slopes | 61K | Well drained | D | Very limited | Very limited |
| Woodward-Deepwood complex, warm, 3 to 5 percent slopes | 38K | Well drained | C | Somewhat limited | Very limited |
| Tilvern clay loam, 1 to 3 percent slopes | 37K | Well drained | D | Very limited | Very limited |
| Woodward-Deepwood-Quinlan complex, warm, 2 to 12 percent slopes | 35K | Well drained | C | Somewhat limited | Very limited |
| Carey loam, 1 to 3 percent slopes | 31K | Well drained | B | Not limited | Somewhat limited |
| Westill clay loam, 0 to 1 percent slopes | 31K | Well drained | D | Very limited | Very limited |
| Deepwood-Woodward-Quinlan complex, warm, 2 to 45 percent slopes | 29K | Well drained | B | Not limited | Somewhat limited |
| Talpa gravelly loam, 1 to 5 percent slopes | 28K | Well drained | D | Very limited | Very limited |
| Vernon-Knoco complex, cool, 1 to 12 percent slopes | 25K | Well drained | D | Somewhat limited | Very limited |
| Rock outcrop-Cottonwood complex, 20 to 45 percent slopes | 19K | D | Very limited | Very limited | |
| Badland and Knoco soils, dry, 2 to 20 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Talpa-Quanah complex, 0 to 3 percent slopes | 15K | Well drained | D | Very limited | Very limited |
| Quanah-Talpa complex, 1 to 8 percent slopes | 12K | Well drained | B | Somewhat limited | Somewhat limited |
| Deepwood-Quinlan-Cottonwood complex, 5 to 50 percent slopes | 12K | Well drained | D | Very limited | Very limited |
| Carey loam, 0 to 1 percent slopes | 11K | Well drained | B | Not limited | Somewhat limited |
| Woodward-Deepwood complex, warm, 5 to 8 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Grandfield fine sandy loam, 1 to 3 percent slopes | 8K | Well drained | B | Not limited | Very limited |
| Quanah silty clay loam, 1 to 3 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| St. Paul silt loam, 0 to 1 percent slopes | 6K | Well drained | C | Somewhat 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 55% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 81% 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.