Soil series profile
Henneke soil series
Henneke is a well drained soil with a gravelly loam surface, mapped on 195,587 acres in 23 counties in CA. Hydrologic group D.
- Drainage class
- Well drained 51% of mapped acres
- Hydrologic group
- D 85% of mapped acres
- Typical topsoil pH
- 6.9 neutral · range 6.7–7.3
- Mapped area
- 196k acres in 23 counties, 1 state
Typical Henneke profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (H1) | Gravelly loam | 6.7 | 24% | 39% | 4.5% |
| 7–15 in (H2) | Very gravelly clay loam | 7.5 | 39% | 30% | 1.25% |
| 15–25 in (H3) | Bedrock | Not reported | Not reported | Not reported | Not reported |

What this means
What Henneke soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Henneke soils is neutral: pH 6.9 (most land between 6.7 and 7.3), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 92% of mapped Henneke acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is gravelly loam (53% of mapped Henneke acres).
42% of mapped Henneke acres is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.
For lawns and yards
On 92% 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 92% of the acres in mapped Henneke soils very limited, 0% somewhat limited and 0% not limited (8% 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 Henneke soil is found
Mapped acres
Henneke is mapped in California.
| County | Acres | Share of county land |
|---|---|---|
| Napa County, CA | 49,390 | 11.2% |
| Lake County, CA | 26,404 | 3.0% |
| Tehama County, CA | 21,006 | 1.1% |
| Colusa County, CA | 19,531 | 2.6% |
| Sonoma County, CA | 12,061 | 1.2% |
| Alameda County, CA | 10,494 | 2.2% |
| Glenn County, CA | 10,223 | 1.2% |
| San Luis Obispo County, CA | 10,149 | 0.6% |
| Mendocino County, CA | 8,509 | 0.4% |
| Monterey County, CA | 6,754 | 0.3% |
| San Benito County, CA | 4,461 | 0.5% |
| Santa Clara County, CA | 3,811 | 0.5% |
| Stanislaus County, CA | 3,761 | 0.4% |
| Marin County, CA | 3,631 | 1.1% |
| Mariposa County, CA | 2,471 | 0.3% |
| Shasta County, CA | 861 | 0.0% |
| Amador County, CA | 540 | 0.1% |
| Placer County, CA | 462 | 0.1% |
| Yolo County, CA | 407 | 0.1% |
| Trinity County, CA | 198 | 0.1% |
| Kings County, CA | 183 | 0.0% |
| Fresno County, CA | 176 | 0.0% |
| Kern County, CA | 10 | 0.0% |
Septic absorption fields
NRCS rating, share of Henneke acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 92.3% |
| Not rated | 7.7% |
Drainage, water table and flooding
Share of Henneke 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 27–53% (median 48%).
- Topsoil organic matter
- Median 4.5%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 26.7% |
| Somewhat excessively drained | 15.3% |
| Well drained | 51.3% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 6.6% |
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 | 7.5% |
| D: very slow infiltration (clayey, shallow or wet) | 84.9% |
| 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% |
| Not rated | 7.7% |
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 Henneke (component kind "Series") in SSURGO: 195,587 acres.
- Method
- Shares are by mapped acres of Henneke components. The profile comes from the single largest Henneke component. Full methodology.