Soil series profile
Kootenai soil series
Kootenai is a well drained soil with a gravelly silt loam surface, mapped on 44,157 acres in 2 counties in ID. Hydrologic group B.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- B 100% of mapped acres
- Typical topsoil pH
- 6.5 slightly acidic · range 6.5–6.5
- Mapped area
- 44k acres in 2 counties, 1 state
Typical Kootenai profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–1 in (Oi) | Slightly decomposed plant material | 6.5 | 15% | 35% | 75% |
| 1–2 in (Oe) | Moderately decomposed plant material | 6.5 | 15% | 35% | 75% |
| 2–8 in (A) | Gravelly silt loam | 6.5 | 7% | 34% | 4.5% |
| 8–24 in (Bw1) | Gravelly silt loam | 6.5 | 7% | 34% | 2% |
| 24–28 in (Bw2) | Very gravelly loam | 6.5 | 9% | 49% | 0.75% |
| 28–62 in (2C) | Extremely gravelly coarse sand | 6.5 | 3% | 91% | 0.25% |
What this means
What Kootenai soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Kootenai soils is slightly acidic: pH 6.5, the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Kootenai acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is gravelly silt loam (68% of mapped Kootenai acres).
100% of mapped Kootenai acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.
For a septic system
For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Kootenai soils very limited, 0% somewhat limited and 0% not limited.
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Kootenai soil is found
Mapped acres
Kootenai is mapped in Idaho.
| County | Acres | Share of county land |
|---|---|---|
| Kootenai County, ID | 31,610 | 4.6% |
| Bonner County, ID | 12,484 | 1.4% |
Septic absorption fields
NRCS rating, share of Kootenai acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 100.0% |
Drainage, water table and flooding
Share of Kootenai acres
- Depth to seasonal high water table
- None reported within about 6.5 feet (median where reported).
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 2–10% (median 4%).
- Topsoil organic matter
- Median 4.5%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 100.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 100.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 0.0% |
| C/D: D as is, C if drained | 0.0% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named Kootenai (component kind "Series") in SSURGO: 44,157 acres.
- Method
- Shares are by mapped acres of Kootenai components. The profile comes from the single largest Kootenai component. Full methodology.