Soil series profile
Atwater soil series
Atwater is a well drained soil with a sand surface, mapped on 65,694 acres in 3 counties in CA. Hydrologic group A.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- A 67% of mapped acres
- Typical topsoil pH
- 6.7 neutral · range 6.7–6.7
- Mapped area
- 66k acres in 3 counties, 1 state
Typical Atwater profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–20 in (H1) | Sand | 6.7 | 4% | 95% | 0.75% |
| 20–32 in (H2) | Sandy loam | 6.7 | 15% | 66% | 0.25% |
| 32–60 in (H3) | Sandy loam | 7.0 | 6% | 65% | 0.25% |
What this means
What Atwater soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Atwater soils is neutral: pH 6.7, the range most vegetables, flowers and lawn grasses prefer.
Sandy topsoil covers 77% of mapped Atwater acres. It drains fast and warms early in spring, but dries out and loses nutrients quickly: mulch, compost and steady watering help. The most common surface texture is loamy sand (59% of mapped Atwater acres).
100% of mapped Atwater acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
67% of mapped acres is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.
For a septic system
For conventional septic absorption fields, NRCS rates 56% of the acres in mapped Atwater soils very limited, 29% somewhat limited and 15% not limited.
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 Atwater soil is found
Mapped acres
Atwater is mapped in California.
| County | Acres | Share of county land |
|---|---|---|
| Merced County, CA | 34,560 | 2.8% |
| Fresno County, CA | 21,060 | 0.4% |
| Madera County, CA | 10,073 | 1.0% |
Septic absorption fields
NRCS rating, share of Atwater acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 14.9% |
| Somewhat limited | 28.8% |
| Very limited | 56.3% |
Drainage, water table and flooding
Share of Atwater 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 1–6% (median 2%).
- 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 | 100.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 66.6% |
| B: moderate infiltration | 32.4% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 1.0% |
| 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% |
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 Atwater (component kind "Series") in SSURGO: 65,694 acres.
- Method
- Shares are by mapped acres of Atwater components. The profile comes from the single largest Atwater component. Full methodology.