Soil series profile
Chilcott soil series
Chilcott is a well drained soil with a silt loam surface, mapped on 208,100 acres in 10 counties across 2 states. Hydrologic group D.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- D >99% of mapped acres
- Typical topsoil pH
- 7.2 neutral · range 6.9–7.2
- Mapped area
- 208k acres in 10 counties, 2 states
Typical Chilcott profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (A/E) | Silt loam | 7.2 | 15% | 30% | 1.5% |
| 7–17 in (Bt) | Silty clay | 7.2 | 48% | 6% | 0.25% |
| 17–27 in (Btk) | Clay loam | 8.2 | 34% | 25% | 0.25% |
| 27–33 in (Bkq) | Loam | 8.5 | 23% | 40% | 0.5% |
| 33–67 in (Bkqm) | Cemented material | Not reported | Not reported | Not reported | Not reported |
What this means
What Chilcott soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Chilcott soils is neutral: pH 7.2 (most land between 6.9 and 7.2), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 98% of mapped Chilcott acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (61% of mapped Chilcott acres).
100% of mapped Chilcott acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 100% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For a septic system
For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Chilcott 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 Chilcott soil is found
Mapped acres
Chilcott is mapped in Idaho and Oregon.
| County | Acres | Share of county land |
|---|---|---|
| Ada County, ID | 54,789 | 9.6% |
| Owyhee County, ID | 46,140 | 1.1% |
| Elmore County, ID | 41,210 | 3.4% |
| Malheur County, OR | 34,251 | 0.5% |
| Gooding County, ID | 13,368 | 3.3% |
| Gem County, ID | 9,283 | 3.3% |
| Lincoln County, ID | 3,547 | 0.5% |
| Canyon County, ID | 2,620 | 0.8% |
| Payette County, ID | 2,591 | 1.2% |
| Washington County, ID | 301 | 0.0% |
Septic absorption fields
NRCS rating, share of Chilcott 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 Chilcott 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 2–7% (median 4%).
- Topsoil organic matter
- Median 1.5%.
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 | 0.0% |
| C: slow infiltration | 0.1% |
| D: very slow infiltration (clayey, shallow or wet) | 99.9% |
| 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 Chilcott (component kind "Series") in SSURGO: 208,100 acres.
- Method
- Shares are by mapped acres of Chilcott components. The profile comes from the single largest Chilcott component. Full methodology.