State soil summary
Soil types in Arizona
The most widespread soil series in Arizona are Gunsight, Sheppard, Denure. Pick a county below, or enter a ZIP code for the county you live in.
- Well or moderately well drained
- 81% of mapped land
- Typical topsoil pH
- 7.9 moderately alkaline · most land 6.8–8.2
- Septic fields very limited
- 62% 9% not limited
- Subject to flooding
- 9% of land, any frequency
Arizona counties
7 county reports, by population
| County | Most common soil | Well drained | Topsoil pH | Septic very limited |
|---|---|---|---|---|
| Maricopa County | Gunsight | 83% | 8.2 | 47% |
| Pima County | Hayhook | 80% | 7.6 | 50% |
| Pinal County | Denure | 80% | 7.9 | 59% |
| Yavapai County | Barkerville | 74% | 7.4 | 68% |
| Mohave County | Mellenthin | 70% | 7.9 | 55% |
| Yuma County | Gunsight | 90% | 8.2 | 57% |
| Coconino County | Winona | 78% | 7.9 | 68% |
What this means
What Arizona soils mean for gardens, lawns and septic systems
For gardens
Typical topsoil in Arizona is moderately alkaline: pH 7.9 (most land between 6.8 and 8.2). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Loamy topsoil (loam, silt loam and similar) covers 65% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is sandy loam (7% of the land).
81% 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 62% of the land in Arizona very limited, 10% somewhat limited and 9% not limited (20% 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 9% of the land (4% occasional, <1% 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 | 5.5% |
| Somewhat excessively drained | 12.3% |
| Well drained | 62.5% |
| Moderately well drained | 0.8% |
| Somewhat poorly drained | 0.3% |
| Poorly drained | 0.1% |
| Very poorly drained | 0.0% |
| Not rated | 18.4% |
Septic absorption fields
Show as a table
| Category | Share of land |
|---|---|
| Not limited | 8.6% |
| Somewhat limited | 9.6% |
| Very limited | 62.0% |
| Not rated | 19.7% |
Topsoil pH
Show as a table
| Category | Share of land |
|---|---|
| Strongly acidic (below 5.5) | 0.0% |
| Moderately to slightly acidic (5.5–6.4) | 3.6% |
| Near neutral (6.5–7.3) | 19.2% |
| Alkaline (7.4 and up) | 57.2% |
| Not reported | 20.0% |
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
- Arizona: 73,163,441 acres of mapped land in 14 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.