Umatilla County Area, Oregon
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 Umatilla County Area, Oregon.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Walla Walla silt loam, 1 to 7 percent slopes | 107K | Well drained | B | Not limited | Somewhat limited |
| Gwin-Rock outcrop complex, 40 to 70 percent slopes | 93K | Well drained | D | Very limited | Very limited |
| Umatilla-Kahler-Gwin association, 35 to 70 percent slopes | 72K | Well drained | B | Very limited | Very limited |
| Athena silt loam, 1 to 7 percent slopes | 45K | Well drained | B | Not limited | Somewhat limited |
| Walla Walla silt loam, 7 to 12 percent slopes | 38K | Well drained | B | Somewhat limited | Somewhat limited |
| Lickskillet very stony loam, 7 to 40 percent slopes | 37K | Well drained | D | Very limited | Very limited |
| Ritzville silt loam, 2 to 7 percent slopes | 34K | Well drained | B | Not limited | Somewhat limited |
| Albee-Bocker-Anatone complex, 2 to 15 percent slopes | 32K | Well drained | D | Very limited | Very limited |
| Tolo silt loam, 3 to 15 percent slopes | 31K | Well drained | C | Somewhat limited | Very limited |
| Pilot Rock silt loam, 1 to 7 percent slopes | 31K | Well drained | C | Somewhat limited | Very limited |
| Buckcreek-Gwin association, 45 to 70 percent slopes | 30K | Well drained | C | Very limited | Very limited |
| Gurdane-Rockly complex, 2 to 20 percent slopes | 30K | Well drained | C | Very limited | Very limited |
| Klicker-Anatone-Bocker complex, 2 to 15 percent slopes | 28K | Well drained | C | Very limited | Very limited |
| Shano silt loam, 2 to 7 percent slopes | 26K | Well drained | B | Not limited | Somewhat limited |
| Morrow silt loam, 1 to 7 percent slopes | 25K | Well drained | C | Very limited | Very limited |
| Ritzville silt loam, 12 to 25 percent slopes | 23K | Well drained | B | Very limited | Very limited |
| Adkins fine sandy loam, 0 to 5 percent slopes | 23K | Well drained | B | Not limited | Somewhat limited |
| Gurdane-Gwinly association, 20 to 40 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Gwinly very cobbly silt loam, 7 to 40 percent slopes | 21K | Well drained | D | Very limited | Very limited |
| Walla Walla silt loam, 12 to 25 percent north slopes | 21K | Well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 56% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 64% 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.