Harper County, Oklahoma
The most common soil here is Quinlan, on about 13% of the land: a loam, a balanced mix that crumbles in your hand. Selman and Woodward come next.
About 96% of the land drains well.
USDA rates 75% of the land very limited for a standard septic drain field, and 41% 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 39% 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 Harper 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 D (very slow infiltration, high runoff). 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 Harper 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 |
|---|---|---|---|---|---|
| Quinlan-Rock outcrop-Yomont complex, 0 to 45 percent slopes | 53K | Well drained | D | Very limited | Very limited |
| Selman silt loam, 1 to 3 percent slopes | 49K | Well drained | B | Not limited | Somewhat limited |
| Quinlan-Woodward-Deepwood complex, 5 to 12 percent slopes | 48K | Well drained | D | Very limited | Very limited |
| Westola-Quinlan-Hardeman complex, 0 to 12 percent slopes | 42K | Well drained | B | Very limited | Very limited |
| Woodward-Quinlan complex, 3 to 5 percent slopes | 35K | Well drained | C | Somewhat limited | Very limited |
| Tivoli fine sand, 5 to 12 percent slopes | 21K | Excessively drained | A | Somewhat limited | Very limited |
| Eda sand, 1 to 12 percent slopes | 21K | Somewhat excessively drained | A | Not limited | Very limited |
| St. Paul silt loam, 1 to 3 percent slopes | 19K | Well drained | C | Somewhat limited | Very limited |
| Selman silt loam, 3 to 5 percent slopes | 18K | Well drained | B | Not limited | Somewhat limited |
| Woodward-Quinlan complex, 1 to 3 percent slopes | 17K | Well drained | C | Somewhat limited | Very limited |
| Cottonwood-Rock outcrop-Vinson complex, 3 to 12 percent slopes | 14K | Well drained | D | Very limited | Very limited |
| Rock outcrop-Cottonwood complex, 12 to 80 percent slopes | 13K | D | Very limited | Very limited | |
| St. Paul silt loam, 0 to 1 percent slopes | 13K | Well drained | C | Somewhat limited | Very limited |
| Hardeman fine sandy loam, 1 to 3 percent slopes, cool | 12K | Well drained | A | Not limited | Very limited |
| Lincoln sand, 0 to 1 percent slopes, occasionally flooded | 12K | Somewhat excessively drained | A | Very limited | Very limited |
| Jester loamy fine sand, 1 to 5 percent slopes | 12K | Excessively drained | A | Not limited | Very limited |
| Tivoli fine sand, 12 to 45 percent slopes | 10K | Excessively drained | A | Very limited | Very limited |
| Alopark-Mocane complex, 1 to 3 percent slopes | 9K | Well drained | A | Not limited | Not limited |
| Grandfield fine sandy loam, 1 to 3 percent slopes | 9K | Well drained | B | Not limited | Very limited |
| Quinlan-Woodward complex, 5 to 8 percent slopes | 9K | Well drained | D | 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 41% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 75% 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.