State soil summary
Soil types in Oklahoma
The most widespread soil series in Oklahoma are Dennis, Stephenville, Carnasaw. Pick a county below, or enter a ZIP code for the county you live in.
- Well or moderately well drained
- 87% of mapped land
- Typical topsoil pH
- 6.5 slightly acidic · most land 5.3–7.9
- Septic fields very limited
- 77% 1% not limited
- Subject to flooding
- 14% of land, any frequency
Oklahoma counties
4 county reports, by population
| County | Most common soil | Well drained | Topsoil pH | Septic very limited |
|---|---|---|---|---|
| Oklahoma County | Stephenville | 81% | 6.3 | 72% |
| Tulsa County | Dennis | 44% | 6.1 | 87% |
| Cleveland County | Stephenville | 92% | 6.4 | 78% |
| Canadian County | Norge | 96% | 6.5 | 58% |
What this means
What Oklahoma soils mean for gardens, lawns and septic systems
For gardens
Typical topsoil in Oklahoma is slightly acidic: pH 6.5 (most land between 5.3 and 7.9), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 79% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (22% of the land).
87% of the land is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 59% of the land, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For septic systems
For conventional septic absorption fields, NRCS rates 77% of the land in Oklahoma very limited, 15% somewhat limited and 1% not limited (6% not rated, such as urban land, pits or water).
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Flooding is mapped on 14% of the land (7% occasional, 5% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Statewide mix
Share of all mapped land
Drainage
Show as a table
| Category | Share of land |
|---|---|
| Excessively drained | 2.0% |
| Somewhat excessively drained | 5.7% |
| Well drained | 68.0% |
| Moderately well drained | 11.6% |
| Somewhat poorly drained | 8.8% |
| Poorly drained | 1.4% |
| Very poorly drained | 0.3% |
| Not rated | 2.3% |
Septic absorption fields
Show as a table
| Category | Share of land |
|---|---|
| Not limited | 1.1% |
| Somewhat limited | 15.4% |
| Very limited | 77.2% |
| Not rated | 6.2% |
Topsoil pH
Show as a table
| Category | Share of land |
|---|---|
| Strongly acidic (below 5.5) | 9.9% |
| Moderately to slightly acidic (5.5–6.4) | 31.4% |
| Near neutral (6.5–7.3) | 31.4% |
| Alkaline (7.4 and up) | 19.4% |
| Not reported | 7.9% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- Oklahoma: 43,829,060 acres of mapped land in 77 counties, pooled (not an average of county figures).
- Method
- Shares are by mapped land area: each map unit’s acres in the county times each soil component’s percentage. Open water is excluded. Topsoil values use the first mineral horizon of each component. Full methodology.