Lewis County Area, Washington
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 Lewis County Area, Washington.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Buckpeak silt loam, 30 to 65 percent slopes | 58K | Well drained | B | Very limited | Very limited |
| Prather silty clay loam, 0 to 5 percent slopes | 44K | Moderately well drained | C | Very limited | Very limited |
| Lacamas silt loam, 0 to 3 percent slopes | 40K | Poorly drained | C/D | Very limited | Very limited |
| Melbourne loam, 15 to 30 percent slopes | 39K | Well drained | C | Very limited | Very limited |
| Pheeney gravelly loam, 30 to 65 percent slopes | 28K | Well drained | C | Very limited | Very limited |
| Melbourne loam, 8 to 15 percent slopes | 27K | Well drained | C | Somewhat limited | Very limited |
| Salkum silty clay loam, 0 to 5 percent slopes | 26K | Well drained | C | Not limited | Very limited |
| Reed silty clay loam | 24K | Poorly drained | D | Very limited | Very limited |
| Cinebar silt loam, 8 to 15 percent slopes | 21K | Well drained | B | Somewhat limited | Somewhat limited |
| Centralia loam, 15 to 30 percent slopes | 20K | Well drained | B | Very limited | Very limited |
| Water | 19K | Not rated | Not rated | ||
| Cattcreek very cindery loamy sand, 30 to 65 percent slopes | 19K | Well drained | B | Very limited | Very limited |
| Katula very cobbly loam, 30 to 65 percent slopes | 18K | Well drained | C | Very limited | Very limited |
| Salkum silty clay loam, 5 to 15 percent slopes | 18K | Well drained | C | Somewhat limited | Very limited |
| Galvin silt loam, 0 to 8 percent slopes | 18K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Cinebar silt loam, 0 to 8 percent slopes | 18K | Well drained | B | Not limited | Somewhat limited |
| Salkum silty clay loam, 15 to 30 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Pheeney-Rock outcrop complex, 65 to 90 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Cinebar silt loam, 15 to 30 percent slopes | 14K | Well drained | B | Very limited | Very limited |
| Baumgard loam, 30 to 65 percent slopes | 14K | Well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 73% 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 88% 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.