Soil series profile
Penrose soil series
Penrose is a well drained soil with a channery loam surface, mapped on 350,596 acres in 19 counties across 5 states. Hydrologic group D.
- Drainage class
- Well drained 98% of mapped acres
- Hydrologic group
- D 99% of mapped acres
- Typical topsoil pH
- 8.2 moderately alkaline · range 8.2–8.2
- Mapped area
- 351k acres in 19 counties, 5 states
Typical Penrose profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–4 in (A) | Channery loam | 8.2 | 21% | 42% | 1% |
| 4–15 in (C) | Channery loam | 8.2 | 23% | 40% | 0.25% |
| 15–79 in (R) | Bedrock | Not reported | Not reported | Not reported | Not reported |
What this means
What Penrose soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Penrose soils is moderately alkaline: pH 8.2. 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 99% of mapped Penrose acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is channery loam (68% of mapped Penrose acres).
99% of mapped Penrose acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 99% 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 99% of the acres in mapped Penrose soils very limited, 0% somewhat limited and 0% not limited (1% 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 Penrose soil is found
Mapped acres
Penrose is mapped in Colorado, South Dakota, New Mexico, Kansas and Wyoming.
| County | Acres | Share of county land |
|---|---|---|
| Pueblo County, CO | 96,518 | 6.4% |
| Las Animas County, CO | 90,434 | 3.0% |
| Otero County, CO | 63,294 | 7.9% |
| Bent County, CO | 31,477 | 3.2% |
| Huerfano County, CO | 15,946 | 1.6% |
| Baca County, CO | 11,168 | 0.7% |
| Fremont County, CO | 9,014 | 1.0% |
| Fall River County, SD | 8,636 | 0.8% |
| Logan County, KS | 7,116 | 1.0% |
| San Miguel County, NM | 6,266 | 0.2% |
| Prowers County, CO | 3,283 | 0.3% |
| Harding County, NM | 2,400 | 0.2% |
| Custer County, SD | 2,400 | 0.3% |
| El Paso County, CO | 1,334 | 0.1% |
| Finney County, KS | 1,032 | 0.1% |
| Mora County, NM | 105 | 0.0% |
| Kiowa County, CO | 26 | 0.0% |
| Custer County, CO | 4 | 0.0% |
| Niobrara County, WY | 2 | 0.0% |
Septic absorption fields
NRCS rating, share of Penrose acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 98.7% |
| Not rated | 1.3% |
Drainage, water table and flooding
Share of Penrose 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 7–25% (median 7%).
- Topsoil organic matter
- Median 1%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.3% |
| Well drained | 98.4% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 1.3% |
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 | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 98.7% |
| 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 | 1.3% |
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 Penrose (component kind "Series") in SSURGO: 350,596 acres.
- Method
- Shares are by mapped acres of Penrose components. The profile comes from the single largest Penrose component. Full methodology.