Walla Walla County Area, Washington
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). 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 Walla Walla County Area, Washington.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Ritzville silt loam, 8 to 30 percent slopes | 131K | Well drained | B | Very limited | Very limited |
| Walla Walla silt loam, 8 to 30 percent slopes | 74K | Well drained | B | Very limited | Very limited |
| Ritzville silt loam, 30 to 45 percent slopes | 35K | Well drained | B | Very limited | Very limited |
| Ritzville silt loam, 0 to 8 percent slopes | 33K | Well drained | B | Not limited | Somewhat limited |
| Walla Walla silt loam, 30 to 45 percent slopes | 28K | Well drained | B | Very limited | Very limited |
| Ritzville very fine sandy loam, 0 to 8 percent slopes | 28K | Well drained | B | Not limited | Somewhat limited |
| Athena silt loam, 8 to 30 percent slopes | 25K | Well drained | B | Very limited | Very limited |
| Ritzville very fine sandy loam, 8 to 30 percent slopes | 24K | Well drained | B | Very limited | Very limited |
| Walla Walla silt loam, 0 to 8 percent slopes | 21K | Well drained | B | Not limited | Somewhat limited |
| Water | 18K | Not rated | Not rated | ||
| Adkins loamy fine sand, 0 to 15 percent slopes | 18K | Well drained | B | Not limited | Somewhat limited |
| Basalt rockland, steep | 17K | Very limited | Very limited | ||
| Quincy fine sand, 0 to 30 percent slopes, eroded | 16K | Excessively drained | A | Very limited | Very limited |
| Adkins fine sandy loam, 0 to 15 percent slopes | 14K | Well drained | B | Not limited | Somewhat limited |
| Palouse silt loam, 8 to 30 percent slopes, eroded | 12K | Well drained | B | Very limited | Very limited |
| Onyx silt loam, 0 to 3 percent slopes | 11K | Well drained | B | Very limited | Very limited |
| Gwin rocky silt loam, 30 to 60 percent slopes | 8K | Well drained | D | Very limited | Very limited |
| Ellisforde silt loam, 15 to 30 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Hezel loamy fine sand, 0 to 15 percent slopes, eroded | 7K | Somewhat excessively drained | C | Not limited | Very limited |
| Quincy loamy fine sand, 0 to 8 percent slopes, eroded | 7K | Excessively drained | A | Not limited | Very limited |
What This Means
Building & Foundations
About 72% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.
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.