Latah County, Idaho
The dominant drainage class is Moderately 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 Latah County, Idaho.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Santa ashy silt loam, 8 to 15 percent slopes | 40K | Moderately well drained | C/D | Very limited | Very limited |
| Larkin silt loam, 12 to 35 percent slopes | 25K | Well drained | C | Very limited | Very limited |
| Southwick silt loam, 12 to 25 percent slopes | 24K | Moderately well drained | C | Very limited | Very limited |
| Taney ashy silt loam, moist, 8 to 25 percent slopes | 24K | Moderately well drained | C | Very limited | Very limited |
| Naff-Palouse complex, 7 to 25 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Norwidge-Threebear complex, 5 to 30 percent slopes | 16K | Well drained | B | Very limited | Very limited |
| Southwick silt loam, dry, 3 to 12 percent slopes | 15K | Moderately well drained | C | Very limited | Very limited |
| Latahco-Thatuna complex, 0 to 5 percent slopes | 14K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Naff-Thatuna complex, 7 to 25 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Santa-Sinkler complex, 20 to 40 percent slopes | 13K | Moderately well drained | C/D | Very limited | Very limited |
| Palouse silt loam, 3 to 7 percent slopes | 10K | Well drained | B | Somewhat limited | Somewhat limited |
| Flewsie, warm-Flewsie, dry-Secunda complex, 35 to 70 percent slopes | 9K | Well drained | B | Very limited | Very limited |
| Palouse silt loam, 7 to 25 percent slopes | 9K | Well drained | B | Very limited | Very limited |
| Tilma-Thatuna complex, 7 to 25 percent slopes | 9K | Moderately well drained | C/D | Very limited | Very limited |
| Bluesprin-Keuterville complex, 35 to 65 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Taney ashy silt loam, dry, 7 to 25 percent slopes | 8K | Moderately well drained | C | Very limited | Very limited |
| Tilma-Naff complex, 7 to 25 percent slopes | 8K | Moderately well drained | C/D | Very limited | Very limited |
| Klickson cobbly ashy loam, 35 to 65 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Carlinton-Carrico-Kruse complex, 8 to 35 percent slopes | 8K | Moderately well drained | D | Very limited | Very limited |
| Taney ashy silt loam, moist, 2 to 8 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 96% 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 96% 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.