State soil summary
Soil types in Rhode Island
The most widespread soil series in Rhode Island are Canton, Charlton, Hinckley. Pick a county below, or enter a ZIP code for the county you live in.
- Well or moderately well drained
- 69% of mapped land
- Typical topsoil pH
- 5.2 strongly acidic · most land 4.3–5.5
- Septic fields very limited
- 85% 4% not limited
- Subject to flooding
- 9% of land, any frequency
Rhode Island counties
3 county reports, by population
| County | Most common soil | Well drained | Topsoil pH | Septic very limited |
|---|---|---|---|---|
| Providence County | Canton | 71% | 5.1 | 83% |
| Kent County | Canton | 73% | 5.1 | 84% |
| Washington County | Canton | 71% | 5.2 | 88% |
What this means
What Rhode Island soils mean for gardens, lawns and septic systems
For gardens
Typical topsoil in Rhode Island is strongly acidic: pH 5.2 (most land between 4.3 and 5.5). Most vegetables and lawn grasses do best around 6.0 to 7.0, so lime is often needed; blueberries, azaleas and rhododendrons like it as it is.
Loamy topsoil (loam, silt loam and similar) covers 73% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is fine sandy loam (47% of the land).
69% of the land 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.
A seasonal high water table comes within 18 inches of the surface on 24% of the land, often in spring. Basements, sump pumps and lawns in low spots feel it first.
For septic systems
For conventional septic absorption fields, NRCS rates 85% of the land in Rhode Island very limited, 7% somewhat limited and 4% 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.
Flooding is mapped on 9% of the land (<1% occasional, 5% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Statewide mix
Share of all mapped land
Drainage
Show as a table
| Category | Share of land |
|---|---|
| Excessively drained | 8.4% |
| Somewhat excessively drained | 7.0% |
| Well drained | 37.9% |
| Moderately well drained | 15.6% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 10.3% |
| Very poorly drained | 8.2% |
| Not rated | 12.6% |
Septic absorption fields
Show as a table
| Category | Share of land |
|---|---|
| Not limited | 3.7% |
| Somewhat limited | 6.9% |
| Very limited | 85.0% |
| Not rated | 4.4% |
Topsoil pH
Show as a table
| Category | Share of land |
|---|---|
| Strongly acidic (below 5.5) | 68.2% |
| Moderately to slightly acidic (5.5–6.4) | 14.3% |
| Near neutral (6.5–7.3) | 0.3% |
| Alkaline (7.4 and up) | 1.8% |
| Not reported | 15.4% |
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
- Rhode Island: 705,076 acres of mapped land in 5 counties, pooled (not an average of county figures).
- Method
- Shares are by mapped land area: each map unit’s acres in the county times each soil component’s percentage. Open water is excluded. Topsoil values use the first mineral horizon of each component. Full methodology.