McClain County, Oklahoma
The most common soil here is Grant, on about 19% of the land: a silt loam, smooth, like flour. Stephenville and Nash come next.
About 91% of the land drains well, and 4% stays wet for long stretches; groundwater comes within two feet of the surface under 5% of it.
USDA rates 70% of the land very limited for a standard septic drain field, and 45% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 17% of the land floods occasionally or more, and bedrock lies within 40 inches under 38% 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 McClain County, Oklahoma, 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 B (moderate infiltration). 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 McClain County, Oklahoma. 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 |
|---|---|---|---|---|---|
| Nash-Lucien complex, 5 to 12 percent slopes | 63K | Well drained | D | Very limited | Very limited |
| Grant silt loam, 3 to 5 percent slopes, eroded | 37K | Well drained | B | Somewhat limited | Somewhat limited |
| Stephenville fine sandy loam, 3 to 5 percent slopes, moderately eroded | 25K | Well drained | C | Somewhat limited | Very limited |
| Nash-Lucien complex, 3 to 5 percent slopes | 13K | Well drained | C | Somewhat limited | Very limited |
| Port silt loam, 0 to 1 percent slopes, occasionally flooded | 13K | Well drained | B | Very limited | Very limited |
| Grant silt loam, 5 to 8 percent slopes, eroded | 13K | Well drained | B | Not limited | Somewhat limited |
| Tamford-Grainola complex, 5 to 12 percent slopes | 13K | Well drained | D | Very limited | Very limited |
| Grant-Port, frequently flooded, complex, 0 to 12 percent slopes | 13K | Well drained | B | Somewhat limited | Somewhat limited |
| Stephenville-Gullied land complex, 1 to 8 percent slopes | 12K | Well drained | C | Somewhat limited | Very limited |
| Gracemore loam, 0 to 1 percent slopes, frequently flooded | 12K | Somewhat poorly drained | A | Very limited | Very limited |
| Renfrow silt loam, 3 to 5 percent slopes, eroded | 12K | Well drained | D | Somewhat limited | Very limited |
| Stephenville fine sandy loam, 3 to 5 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Keokuk silt loam, 0 to 1 percent slopes, occasionally flooded | 10K | Well drained | B | Very limited | Very limited |
| Water | 8K | D | Not rated | Not rated | |
| Kirkland silt loam, 1 to 3 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Pulaski fine sandy loam, 0 to 1 percent slopes, occasionally flooded | 7K | Well drained | A | Very limited | Very limited |
| Grant silt loam, 3 to 5 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| Pond Creek silt loam, 1 to 3 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| Gullied land-Grant complex, 3 to 8 percent slopes | 7K | Well drained | C | Not limited | Very limited |
| Ashport, Port and Pulaski soils, 0 to 1 percent slopes, frequently flooded | 7K | Well drained | B | 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 45% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 70% 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.