Collin County, Texas
The most common soil here is Houston Black, on about 39% of the land: a clay, sticky when wet and rock-hard when dry. Heiden and Austin come next.
About 37% of the land drains well.
USDA rates 95% of the land very limited for a standard septic drain field, and 79% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 9% of the land floods occasionally or more, and bedrock lies within 40 inches under 18% 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 Collin 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 Moderately well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Vertisols — clay-rich soils that shrink and swell dramatically with moisture changes. 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 Collin 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 |
|---|---|---|---|---|---|
| Houston Black clay, 1 to 3 percent slopes | 190K | Moderately well drained | D | Very limited | Very limited |
| Houston Black clay, 0 to 1 percent slopes | 42K | Moderately well drained | D | Very limited | Very limited |
| Austin silty clay, 2 to 5 percent slopes, moderately eroded | 32K | Well drained | D | Somewhat limited | Very limited |
| Heiden clay, 3 to 5 percent slopes, eroded | 29K | Well drained | D | Very limited | Very limited |
| Austin silty clay, 1 to 3 percent slopes | 26K | Well drained | D | Somewhat limited | Very limited |
| Water | 24K | D | Not rated | Not rated | |
| Houston Black clay, 2 to 4 percent slopes, eroded | 23K | Moderately well drained | D | Very limited | Very limited |
| Tinn clay, 0 to 1 percent slopes, frequently flooded | 22K | Moderately well drained | D | Very limited | Very limited |
| Heiden clay, 5 to 8 percent slopes, eroded | 21K | Well drained | D | Very limited | Very limited |
| Tinn clay, 0 to 1 percent slopes, occasionally flooded | 20K | Moderately well drained | D | Very limited | Very limited |
| Altoga silty clay, 5 to 8 percent slopes, eroded | 17K | Well drained | C | Somewhat limited | Very limited |
| Ferris-Heiden clay, 5 to 12 percent slopes, severely eroded | 14K | Well drained | D | Very limited | Very limited |
| Eddy gravelly clay loam, 3 to 8 percent slopes, eroded | 14K | Well drained | D | Very limited | Very limited |
| Austin silty clay, 5 to 8 percent slopes, moderately eroded | 13K | Well drained | D | Somewhat limited | Very limited |
| Lewisville silty clay, 3 to 5 percent slopes, eroded | 12K | Well drained | C | Very limited | Very limited |
| Burleson clay, 1 to 3 percent slopes | 11K | Moderately well drained | D | Very limited | Very limited |
| Wilson clay loam, 1 to 3 percent slopes | 10K | Moderately well drained | C | Very limited | Very limited |
| Stephen silty clay, 1 to 4 percent slopes | 8K | Well drained | D | Very limited | Very limited |
| Stephen-Eddy complex, 2 to 5 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Frio clay loam, occasionally flooded | 5K | 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.
What This Means
Building & Foundations
About 79% 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 95% 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.