Valley Area, Idaho, Parts of Adams and Valley Counties
The most common soil here is Shellrock, on about 6% of the land: a coarse sand, loose sand that holds almost no water. Archabal and Bryan come next.
About 70% of the land drains well, and 13% stays wet for long stretches; groundwater comes within two feet of the surface under 13% of it.
USDA rates 87% of the land very limited for a standard septic drain field, and 71% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 13% of the land floods occasionally or more, and bedrock lies within 40 inches under 39% 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 Valley Area, Idaho, Parts of Adams and Valley Counties, 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 A (high infiltration, low runoff). The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols. 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 Valley Area, Idaho, Parts of Adams and Valley Counties. 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 |
|---|---|---|---|---|---|
| Water | 35K | Not rated | Not rated | ||
| Bryan-Pyle complex, 40 to 60 percent slopes | 22K | Excessively drained | A | Very limited | Very limited |
| Pyle-Koppes complex, 40 to 60 percent slopes | 21K | Somewhat excessively drained | A | Very limited | Very limited |
| Shellrock-Rock outcrop complex, 30 to 60 percent slopes | 18K | Somewhat excessively drained | A | Very limited | Very limited |
| Jugson coarse sandy loam, 30 to 60 percent slopes | 16K | Somewhat excessively drained | B | Very limited | Very limited |
| Roseberry coarse sandy loam, occasionally flooded | 15K | Poorly drained | B | Very limited | Very limited |
| Archabal loam, 4 to 12 percent slopes | 14K | Well drained | B | Not limited | Very limited |
| Quartzburg-Bryan complex, 10 to 45 percent slopes | 13K | Excessively drained | A | Very limited | Very limited |
| McCall complex, 5 to 50 percent slopes | 10K | Somewhat excessively drained | A | Very limited | Very limited |
| Donnel sandy loam, 0 to 2 percent slopes | 10K | Well drained | A | Not limited | Very limited |
| Blackwell silt loam, frequently flooded | 8K | Very poorly drained | C/D | Very limited | Very limited |
| Shellrock loamy coarse sand, 35 to 60 percent slopes | 8K | Somewhat excessively drained | A | Very limited | Very limited |
| Archabal loam, 2 to 4 percent slopes | 8K | Well drained | B | Not limited | Very limited |
| Melton loam | 7K | Poorly drained | B/D | Very limited | Very limited |
| Gestrin loam, 2 to 4 percent slopes, rarely flooded | 7K | Moderately well drained | B | Very limited | Very limited |
| Donnel sandy loam, 2 to 4 percent slopes | 6K | Well drained | A | Not limited | Very limited |
| Roseberry, occasionally flooded-Melton, frequently flooded-Jurvannah, frequently flooded complex | 5K | Poorly drained | B | Very limited | Very limited |
| Rock outcrop | 5K | D | Not rated | Not rated | |
| Shellrock-Rock outcrop complex, 2 to 25 percent slopes | 5K | Somewhat excessively drained | A | Very limited | Very limited |
| Shellrock loamy coarse sand, 12 to 35 percent slopes | 5K | Somewhat excessively drained | A | 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 71% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas, sandy or gravelly soils with low bearing capacity. A geotechnical assessment is recommended before building.
Septic Systems
About 87% 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.