Star Valley Area, Wyoming-Idaho
The most common soil here is Paulson, on about 9% of the land: a silt loam, smooth, like flour. Greyback and Robana come next.
About 82% of the land drains well, and 7% stays wet for long stretches; groundwater comes within two feet of the surface under 7% of it.
USDA rates 72% of the land very limited for a standard septic drain field, and 54% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 12% of the land floods occasionally or more, and bedrock lies within 40 inches under 6% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Star Valley Area, Wyoming-Idaho, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. 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 Star Valley Area, Wyoming-Idaho. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Paulson-Lail association | 13K | Well drained | C | Very limited | Very limited |
| Greyback gravelly loam | 10K | Somewhat excessively drained | B | Not limited | Very limited |
| Osmund and Mundos gravelly loams, 0 to 3 percent slopes | 10K | Well drained | B | Not limited | Somewhat limited |
| Turson silt loam, 0 to 3 percent slopes, frequently flooded | 9K | Moderately well drained | B | Very limited | Very limited |
| Hobacker gravelly loam | 7K | Somewhat excessively drained | B | Not limited | Very limited |
| Leavittville silt loam, 0 to 3 percent slopes | 7K | Well drained | B | Not limited | Somewhat limited |
| Cowdrey clay loam, 10 to 30 percent slopes | 7K | Well drained | C | Very limited | Very limited |
| Greyback-Rooset association, hilly | 7K | Well drained | B | Very limited | Very limited |
| Greyback-Rooset association, steep | 7K | Well drained | B | Very limited | Very limited |
| Paulson-Rockland complex, 30 to 60 percent slopes | 6K | Not rated | Not rated | ||
| Cryaquolls and Cryaquepts | 6K | Poorly drained | D | Not rated | Not rated |
| Lail-Cowdrey association | 6K | Well drained | C | Very limited | Very limited |
| Buckskin-Decross association, hilly | 5K | Well drained | C | Very limited | Very limited |
| Paulson silty clay loam, 0 to 3 percent slopes | 5K | Well drained | C | Somewhat limited | Very limited |
| Robana-Turnerville association, hilly | 4K | Well drained | B | Very limited | Very limited |
| Buckskin-Decross association, undulating | 4K | Well drained | C | Very limited | Very limited |
| Water | 4K | Not rated | Not rated | ||
| Dipman-Narrows association | 4K | Poorly drained | C/D | Very limited | Very limited |
| Robana silt loam, 10 to 20 percent slopes | 3K | Well drained | B | Very limited | Very limited |
| Greyback and Hobacker soils, 0 to 30 percent slopes | 3K | Somewhat excessively drained | B | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 54% 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 72% 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.