Boise County Area, Idaho, Western Part
The most common soil here is Shirts, on about 9% of the land: a coarse sandy loam, gritty and crumbly. Charters and Kosh come next.
About 98% of the land drains well.
USDA rates 99% of the land very limited for a standard septic drain field, and 97% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 87% 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 Boise County Area, Idaho, Western 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 Somewhat excessively 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 Boise County Area, Idaho, Western 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 |
|---|---|---|---|---|---|
| Robbscreek-Dobson-Brownlee complex, 25 to 65 percent slopes | 17K | Well drained | C | Very limited | Very limited |
| Deerrun-Kisky-Drybuck complex, 35 to 90 percent slopes | 16K | Somewhat excessively drained | B | Very limited | Very limited |
| Charters-Shirts-Kosh complex, 25 to 65 percent slopes | 15K | Somewhat excessively drained | A | Very limited | Very limited |
| Backswitch-Charters-Zimmer complex, 8 to 50 percent slopes | 14K | Somewhat excessively drained | B | Very limited | Very limited |
| Charters-Crumley-Eagleson complex, 35 to 90 percent slopes | 14K | Somewhat excessively drained | A | Very limited | Very limited |
| Shirts-Kosh-Charters complex, 25 to 65 percent slopes | 13K | Somewhat excessively drained | B | Very limited | Very limited |
| Shirts-Kosh-Charters complex, 15 to 50 percent slopes | 12K | Somewhat excessively drained | B | Very limited | Very limited |
| Eagleson-Kosh complex, 25 to 90 percent slopes | 11K | Somewhat excessively drained | B | Very limited | Very limited |
| Shirts-Zimmer-Charters complex, 35 to 90 percent slopes | 11K | Somewhat excessively drained | B | Very limited | Very limited |
| Charters-Shirts-Zimmer complex, 35 to 90 percent slopes | 11K | Somewhat excessively drained | A | Very limited | Very limited |
| Roney-Kisky-Olaton complex, 25 to 65 percent slopes | 11K | Somewhat excessively drained | B | Very limited | Very limited |
| Brownlee-Robbscreek-Whisk complex, 8 to 35 percent slopes | 11K | Well drained | C | Very limited | Very limited |
| Shimo-Kisky-Schiller complex, 35 to 90 percent slopes | 10K | Excessively drained | A | Very limited | Very limited |
| Garval-Kisky complex, 35 to 90 percent slopes | 10K | Excessively drained | A | Very limited | Very limited |
| Pajo-Packerjohn-Kosh complex, 35 to 90 percent slopes | 9K | Excessively drained | A | Very limited | Very limited |
| Shirts-Kosh complex, 35 to 90 percent slopes | 9K | Somewhat excessively drained | B | Very limited | Very limited |
| Dobson-Roney complex, 35 to 90 percent slopes | 9K | Somewhat excessively drained | D | Very limited | Very limited |
| Eagleson-Kosh-Charters complex, 35 to 90 percent slopes | 8K | Somewhat excessively drained | B | Very limited | Very limited |
| Northfork-Shirts-Zimmer complex, 35 to 90 percent slopes | 8K | Somewhat excessively drained | A | Very limited | Very limited |
| Cartwright-Brownlee-Robbscreek complex, 25 to 65 percent slopes | 7K | Well drained | C | 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 97% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, sandy or gravelly soils with low bearing capacity. A geotechnical assessment is recommended before building.
Septic Systems
About 99% of soils are rated "very limited" for septic absorption fields. The well-drained soils may actually drain too fast for standard leach fields, allowing effluent to reach groundwater. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Soils tend to drain very quickly, meaning nutrients and water don't stick around long. Raised beds with amended soil, drip irrigation, and heavy mulching will give the best results. Compost is your best friend here — it improves water retention dramatically.