Cassia County, Idaho, West Part
The most common soil here is Portneuf, on about 10% of the land: a silt loam, smooth, like flour. Buko and Paniogue come next.
About 86% of the land drains well, and 6% stays wet for long stretches.
USDA rates 69% of the land very limited for a standard septic drain field, and 40% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: bedrock lies within 40 inches under 23% 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 Cassia County, Idaho, West Part, 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 C (slow infiltration, moderate runoff). The most common soil order is Aridisols — dry-climate soils with limited organic matter and often calcium carbonate accumulation. 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 Cassia County, Idaho, West Part. 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 |
|---|---|---|---|---|---|
| Buko-Paniogue complex | 31K | Well drained | C | Not limited | Somewhat limited |
| Mackey-Rock outcrop complex | 21K | Well drained | C | Very limited | Very limited |
| Aysees gravelly loam, 1 to 12 percent slopes | 17K | Somewhat excessively drained | B | Not limited | Very limited |
| Drax silt loam | 17K | Moderately well drained | C | Very limited | Very limited |
| Portneuf silt loam, 1 to 3 percent slopes | 17K | Well drained | C | Not limited | Very limited |
| Weeks loam, 1 to 3 percent slopes | 14K | Well drained | C | Somewhat limited | Very limited |
| Portneuf silt loam, 0 to 1 percent slopes | 13K | Well drained | C | Not limited | Very limited |
| Bedke silt loam, 3 to 12 percent slopes | 12K | Well drained | C | Not limited | Somewhat limited |
| Declo loam, 0 to 1 percent slopes | 11K | Well drained | B | Not limited | Somewhat limited |
| Itca-Kanlee complex | 10K | Well drained | D | Very limited | Very limited |
| Alpowa gravelly loam, 20 to 60 percent slopes | 10K | Well drained | A | Very limited | Very limited |
| Wodskow sandy loam, drained | 9K | Well drained | A | Very limited | Somewhat limited |
| Reywat gravelly loam, 0 to 30 percent slopes | 8K | Well drained | D | Very limited | Very limited |
| Portneuf silt loam, 3 to 7 percent slopes | 7K | Well drained | C | Not limited | Very limited |
| Paniogue-Buko complex | 7K | Well drained | B | Not limited | Very limited |
| Beetville loam | 7K | Moderately well drained | B | Somewhat limited | Very limited |
| Trevino-Rock outcrop complex | 7K | Well drained | D | Very limited | Very limited |
| Mulett very cobbly loam, 4 to 20 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Wodskow sandy loam | 6K | Somewhat poorly drained | B | Very limited | Very limited |
| Alpowa loam, 3 to 12 percent slopes | 6K | Well drained | A | Somewhat 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 40% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 69% 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.