Soil series profile
Nunn soil series
Nunn is a well drained soil with a clay loam surface, mapped on 865,875 acres in 34 counties across 4 states. Hydrologic group C.
- Drainage class
- Well drained 97% of mapped acres
- Hydrologic group
- C 98% of mapped acres
- Typical topsoil pH
- 7.0 neutral · range 7.0–7.2
- Mapped area
- 866k acres in 34 counties, 4 states
Typical Nunn profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (A) | Clay loam | 7.0 | 34% | 29% | 3% |
| 7–23 in (Bt) | Clay | 7.2 | 43% | 26% | 1% |
| 23–79 in (Ck) | Clay loam | 7.9 | 33% | 30% | 0.5% |
What this means
What Nunn soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Nunn soils is neutral: pH 7.0 (most land between 7.0 and 7.2), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 99% of mapped Nunn acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is clay loam (50% of mapped Nunn acres).
97% of mapped Nunn 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 97% of the acres in mapped Nunn soils very limited, <1% somewhat limited and 1% 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 Nunn soil is found
Mapped acres
Nunn is mapped in Colorado, South Dakota, Montana and Wyoming.
| County | Acres | Share of county land |
|---|---|---|
| Pennington County, SD | 135,711 | 7.6% |
| Meade County, SD | 120,884 | 5.5% |
| Weld County, CO | 115,726 | 4.5% |
| Logan County, CO | 42,821 | 3.6% |
| Arapahoe County, CO | 41,537 | 8.0% |
| Larimer County, CO | 34,612 | 2.1% |
| Jackson County, SD | 34,302 | 2.9% |
| Elbert County, CO | 31,665 | 2.7% |
| Boulder County, CO | 27,631 | 6.0% |
| Morgan County, CO | 26,834 | 3.3% |
| Jefferson County, CO | 24,174 | 5.9% |
| Adams County, CO | 21,061 | 2.8% |
| Big Horn County, MT | 18,979 | 0.4% |
| Fall River County, SD | 14,272 | 1.3% |
| Kit Carson County, CO | 13,349 | 1.0% |
| Treasure County, MT | 12,007 | 1.9% |
| Huerfano County, CO | 11,084 | 1.1% |
| Pueblo County, CO | 10,186 | 0.7% |
| El Paso County, CO | 10,132 | 0.7% |
| Washington County, CO | 9,892 | 0.6% |
| Crook County, WY | 9,534 | 0.5% |
| Cheyenne County, CO | 8,679 | 0.8% |
| Butte County, SD | 8,266 | 0.6% |
| Fremont County, CO | 6,552 | 0.7% |
| Carbon County, MT | 6,269 | 0.5% |
| Lincoln County, CO | 5,177 | 0.3% |
| Broomfield County, CO | 5,021 | 17.7% |
| Custer County, CO | 4,317 | 0.9% |
| Baca County, CO | 2,845 | 0.2% |
| Haakon County, SD | 2,793 | 0.2% |
| Denver County, CO | 1,633 | 1.6% |
| Douglas County, CO | 1,203 | 0.2% |
| Laramie County, WY | 25 | 0.0% |
| Park County, CO | 0 | 0.0% |
Septic absorption fields
NRCS rating, share of Nunn acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 1.1% |
| Somewhat limited | 0.7% |
| Very limited | 97.2% |
| Not rated | 1.0% |
Drainage, water table and flooding
Share of Nunn acres
- Depth to seasonal high water table
- About 3.9 feet (47 in) (median where reported).
- Flooding
- Mapped as flooding on <1% of acres (0% occasional, 0% frequent).
- Slope
- Typically 1–6% (median 2%).
- Topsoil organic matter
- Median 2%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 97.3% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 2.2% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 0.5% |
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 | 98.3% |
| D: very slow infiltration (clayey, shallow or wet) | 0.8% |
| 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 | 0.9% |
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 Nunn (component kind "Series") in SSURGO: 865,875 acres.
- Method
- Shares are by mapped acres of Nunn components. The profile comes from the single largest Nunn component. Full methodology.