Collin County, Texas
The dominant drainage class is Moderately well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). 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.
| 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 |
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.