Soil series profile
Lompico soil series
Lompico is a well drained soil with a loam surface, mapped on 37,799 acres in 3 counties in CA. Hydrologic group C.
- Drainage class
- Well drained 92% of mapped acres
- Hydrologic group
- C 91% of mapped acres
- Typical topsoil pH
- 6.5 slightly acidic · range 6.3–6.7
- Mapped area
- 38k acres in 3 counties, 1 state
Typical Lompico profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–17 in (H1) | Loam | 6.7 | 18% | 43% | 2% |
| 17–32 in (H2) | Loam | 5.3 | 28% | 37% | 0.75% |
| 32–59 in (H3) | Weathered bedrock | Not reported | Not reported | Not reported | Not reported |
What this means
What Lompico soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Lompico soils is slightly acidic: pH 6.5 (most land between 6.3 and 6.7), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 91% of mapped Lompico acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (91% of mapped Lompico acres).
92% of mapped Lompico acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 91% 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 91% of the acres in mapped Lompico soils very limited, 0% somewhat limited and 0% not limited (9% 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 Lompico soil is found
Mapped acres
Lompico is mapped in California.
| County | Acres | Share of county land |
|---|---|---|
| San Luis Obispo County, CA | 19,167 | 1.2% |
| Santa Cruz County, CA | 18,471 | 6.7% |
| Santa Clara County, CA | 161 | 0.0% |
Septic absorption fields
NRCS rating, share of Lompico acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 91.0% |
| Not rated | 9.0% |
Drainage, water table and flooding
Share of Lompico 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 18–63% (median 53%).
- 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 | 92.1% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 7.9% |
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 | 90.9% |
| D: very slow infiltration (clayey, shallow or wet) | 0.1% |
| 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 | 9.0% |
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 Lompico (component kind "Series") in SSURGO: 37,799 acres.
- Method
- Shares are by mapped acres of Lompico components. The profile comes from the single largest Lompico component. Full methodology.