Soil series profile
Killpack soil series
Killpack is a well drained soil with a parachannery silty clay loam surface, mapped on 145,020 acres in 10 counties across 2 states. Hydrologic group C.
- Drainage class
- Well drained 97% of mapped acres
- Hydrologic group
- C 56% of mapped acres
- Typical topsoil pH
- 8.2 moderately alkaline · range 7.9–8.5
- Mapped area
- 145k acres in 10 counties, 2 states
Typical Killpack profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–3 in (A) | Parachannery silty clay loam | 7.9 | 30% | 6% | 0.75% |
| 3–12 in (Byz1) | Parachannery silty clay loam | 8.3 | 32% | 7% | 0.25% |
| 12–26 in (Byz2) | Parachannery silty clay loam | 8.4 | 34% | 6% | 0.25% |
| 26–36 in (Byz3) | Extremely parachannery silty clay loam | 8.4 | 36% | 4% | 0.25% |
| 36–60 in (Cr) | Bedrock | Not reported | Not reported | Not reported | Not reported |
What this means
What Killpack soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Killpack soils is moderately alkaline: pH 8.2 (most land between 7.9 and 8.5). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Loamy topsoil (loam, silt loam and similar) covers 86% of mapped Killpack acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silty clay loam (33% of mapped Killpack acres).
97% of mapped Killpack acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 96% 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 96% of the acres in mapped Killpack soils very limited, 0% somewhat limited and 0% not limited (4% not rated, such as urban land, pits or water).
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 Killpack soil is found
Mapped acres
Killpack is mapped in Colorado and Utah.
| County | Acres | Share of county land |
|---|---|---|
| Mesa County, CO | 49,789 | 3.2% |
| Grand County, UT | 37,750 | 1.7% |
| Emery County, UT | 25,713 | 1.0% |
| Montrose County, CO | 7,843 | 1.3% |
| Delta County, CO | 6,045 | 1.1% |
| Carbon County, UT | 5,700 | 0.6% |
| Rio Blanco County, CO | 3,413 | 0.2% |
| Gunnison County, CO | 2,034 | 0.1% |
| Sevier County, UT | 441 | 0.1% |
| Ouray County, CO | 58 | 0.0% |
Septic absorption fields
NRCS rating, share of Killpack acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 95.6% |
| Not rated | 4.4% |
Drainage, water table and flooding
Share of Killpack 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 2–18% (median 8%).
- Topsoil organic matter
- Median 0.8%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 96.5% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 3.5% |
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 | 56.4% |
| D: very slow infiltration (clayey, shallow or wet) | 39.2% |
| 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% |
| Not rated | 4.4% |
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 Killpack (component kind "Series") in SSURGO: 145,020 acres.
- Method
- Shares are by mapped acres of Killpack components. The profile comes from the single largest Killpack component. Full methodology.