Knox County, Texas
The most common soil here is Knoco, on about 13% of the land: a clay, sticky when wet and rock-hard when dry. Miles and Vernon come next.
About 98% of the land drains well.
USDA rates 87% of the land very limited for a standard septic drain field, and 53% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 10% of the land floods occasionally or more, and bedrock lies within 40 inches under 36% 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 Knox 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 Knox 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 |
|---|---|---|---|---|---|
| Knoco-Badland complex, 1 to 12 percent slopes | 100K | Well drained | D | Very limited | Very limited |
| Miles fine sandy loam, moist, 0 to 1 percent slopes | 39K | Well drained | B | Somewhat limited | Somewhat limited |
| Cottonwood-Knoco complex, 3 to 20 percent slopes | 38K | Well drained | D | Very limited | Very limited |
| Miles fine sandy loam, moist, 1 to 3 percent slopes | 23K | Well drained | B | Somewhat limited | Somewhat limited |
| Grandfield-Devol complex, 0 to 3 percent slopes | 22K | Well drained | B | Not limited | Very limited |
| Hollister clay loam, 0 to 1 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Mangum clay, frequently flooded | 21K | Well drained | D | Very limited | Very limited |
| Rotan clay loam, 0 to 1 percent slopes | 20K | Well drained | C | Somewhat limited | Very limited |
| Knoco-Vernon complex, 3 to 12 percent slopes | 17K | Well drained | D | Very limited | Very limited |
| Vernon clay, 3 to 8 percent slopes | 17K | Well drained | D | Somewhat limited | Very limited |
| Tillman clay loam, 1 to 3 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Tillman clay loam, 0 to 1 percent slopes | 15K | Well drained | C | Very limited | Very limited |
| Sagerton clay loam, moist, 0 to 1 percent slopes | 14K | Well drained | C | Somewhat limited | Very limited |
| Clairemont silt loam, 0 to 1 percent slopes, frequently flooded | 13K | Well drained | B | Very limited | Very limited |
| Rotan-Winters-Miles complex, 0 to 1 percent slopes | 12K | Well drained | C | Somewhat limited | Very limited |
| Wichita clay loam, 0 to 1 percent slopes | 10K | Well drained | C | Somewhat limited | Very limited |
| Lincoln-Westola complex, occasionally flooded | 10K | Somewhat excessively drained | A | Very limited | Very limited |
| Cosh fine sandy loam, 1 to 5 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Altus fine sandy loam, warm, 0 to 1 percent slopes | 9K | Well drained | B | Not limited | Very limited |
| Enterprise very fine sandy loam, 0 to 1 percent slopes | 8K | Well drained | A | Not 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 53% 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 87% 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.