Jefferson County Area, Washington
The dominant drainage class is Moderately 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 Jefferson County Area, Washington.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Dimal very flaggy silty clay loam, 50 to 90 percent slopes | 49K | Somewhat excessively drained | D | Very limited | Very limited |
| Solleks channery silty clay loam, 30 to 50 percent slopes | 32K | Well drained | B | Very limited | Very limited |
| Hoko gravelly silt loam, 0 to 15 percent slopes | 25K | Moderately well drained | C | Very limited | Very limited |
| Hoko-Snahopish association, hilly | 17K | Moderately well drained | C | Very limited | Very limited |
| Alderwood gravelly sandy loam, 0 to 15 percent slopes | 16K | Moderately well drained | B | Very limited | Very limited |
| Skookumcreek-Bonjonpass-Mountscott complex, 0 to 100 percent slopes | 15K | Well drained | A | Very limited | Very limited |
| Klone-Hoko association, moderately steep | 15K | Well drained | B | Very limited | Very limited |
| Sinclair gravelly sandy loam, 0 to 15 percent slopes | 13K | Moderately well drained | B | Very limited | Very limited |
| Calawah silt loam, 0 to 8 percent slopes | 12K | Moderately well drained | B | Not limited | Somewhat limited |
| Mountdeception-Irely complex, 35 to 100 percent slopes | 11K | Well drained | A | Very limited | Very limited |
| Willapa-Calawah complex, 15 to 45 percent slopes | 9K | Moderately well drained | B/D | Very limited | Very limited |
| Clallam gravelly sandy loam, 0 to 15 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Alderwood gravelly sandy loam, 15 to 30 percent slopes | 7K | Moderately well drained | B | Very limited | Very limited |
| Snahopish silty clay loam, 0 to 30 percent slopes | 6K | Well drained | B | Very limited | Very limited |
| Alderwood gravelly loam, 0 to 15 percent slopes | 6K | Moderately well drained | B | Very limited | Very limited |
| Sinclair gravelly sandy loam, 15 to 30 percent slopes | 6K | Moderately well drained | B | Very limited | Very limited |
| Jolleycreek-Saghalie complex, 0 to 60 percent slopes | 6K | Well drained | A | Very limited | Very limited |
| Itswoot very cobbly silt loam, 0 to 30 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Hoko-Tealwhit association, gently rolling | 5K | Moderately well drained | C | Very limited | Very limited |
| Dabob very gravelly sandy loam, 0 to 15 percent slopes | 5K | Moderately well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 95% 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 95% 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.