Yamhill County, Oregon
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). 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 Yamhill County, Oregon.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Woodburn silt loam, 0 to 3 percent slopes | 33K | Moderately well drained | C | Very limited | Very limited |
| Amity silt loam, 0 to 3 percent slopes | 19K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Woodburn silt loam, 3 to 12 percent slopes | 12K | Moderately well drained | C | Very limited | Very limited |
| Olyic silt loam, 30 to 60 percent slopes | 11K | Well drained | B | Very limited | Very limited |
| Olyic silt loam, 5 to 30 percent slopes | 11K | Well drained | B | Very limited | Very limited |
| Hembre silt loam, 30 to 60 percent slopes | 11K | Well drained | B | Very limited | Very limited |
| Hemcross-Klistan complex, 30 to 60 percent slopes | 10K | Well drained | B | Very limited | Very limited |
| Peavine silty clay loam, 30 to 60 percent slopes | 10K | Well drained | C | Very limited | Very limited |
| Chehalis silty clay loam, 0 to 3 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Astoria silt loam 30 to 60 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Astoria silt loam, 5 to 30 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Hembre silt loam, 3 to 30 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Dayton silt loam, 0 to 2 percent slopes | 7K | Poorly drained | D | Very limited | Very limited |
| Jory-Bellpine complex, 12 to 20 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Woodburn silt loam, 20 to 55 percent slopes | 6K | Moderately well drained | C | Very limited | Very limited |
| Melbourne-Goodin silty clay loams, 12 to 20 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Saum silty clay loam, hummocky, 12 to 30 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Witham silty clay loam, hummocky, 2 to 25 percent slopes | 6K | Somewhat poorly drained | D | Very limited | Very limited |
| Peavine silty clay loam, 2 to 30 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Jory-Bellpine complex, 20 to 30 percent slopes | 5K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 100% 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.