Soil series profile
Ridd soil series
Ridd is a well drained soil with a very cobbly sandy loam surface, mapped on 19,093 acres in 3 counties in UT. Hydrologic group B.
- Drainage class
- Well drained 96% of mapped acres
- Hydrologic group
- B 81% of mapped acres
- Typical topsoil pH
- 7.0 neutral · range 7.0–7.0
- Mapped area
- 19k acres in 3 counties, 1 state
Typical Ridd profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–5 in (A11) | Very cobbly sandy loam | 7.0 | 10% | 67% | 2% |
| 5–9 in (A12) | Very cobbly sandy loam | 7.0 | 13% | 68% | 2% |
| 9–18 in (B2t) | Very cobbly sandy loam | 7.0 | 17% | 65% | 0.75% |
| 18–26 in (B3) | Very gravelly sandy loam | 7.0 | 17% | 65% | 0.25% |
| 26–36 in (C) | Extremely gravelly sandy loam | 7.0 | 10% | 67% | 0.25% |
| 36–46 in (R) | Unweathered bedrock | Not reported | Not reported | Not reported | Not reported |
What this means
What Ridd soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Ridd soils is neutral: pH 7.0, the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 96% of mapped Ridd acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is very stony sandy loam (43% of mapped Ridd acres).
96% of mapped Ridd acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.
For a septic system
For conventional septic absorption fields, NRCS rates 96% of the acres in mapped Ridd soils very limited, 0% somewhat limited and 0% not limited (4% 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 Ridd soil is found
Mapped acres
Ridd is mapped in Utah.
| County | Acres | Share of county land |
|---|---|---|
| Davis County, UT | 13,778 | 9.6% |
| Box Elder County, UT | 4,013 | 0.1% |
| Weber County, UT | 1,302 | 0.4% |
Septic absorption fields
NRCS rating, share of Ridd acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 95.7% |
| Not rated | 4.3% |
Drainage, water table and flooding
Share of Ridd 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 13–50% (median 20%).
- Topsoil organic matter
- Median 3%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 95.7% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 4.3% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 81.3% |
| C: slow infiltration | 14.4% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| 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% |
| Not rated | 4.3% |
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 Ridd (component kind "Series") in SSURGO: 19,093 acres.
- Method
- Shares are by mapped acres of Ridd components. The profile comes from the single largest Ridd component. Full methodology.