County soil summary
Soil types in Plymouth County, Massachusetts
The most widespread soils are Carver, Freetown and Hinckley; the most common drainage class is excessively drained (26% of the land), and typical topsoil pH is 4.8.
- Well or moderately well drained
- 66% of land · state 72%
- Typical topsoil pH
- 4.8 very strongly acidic · state 5.0
- Septic fields very limited
- 94% of land · state 88%
- Subject to flooding
- 16% of land, any frequency · state 8%
Most common soils in Plymouth County
Share of mapped land
A county is a patchwork of many soils. These 8 cover 45% of the mapped land; 57 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| Carver | 11.5% | Excessively drained | 4.0 |
| Freetown | 6.3% | Very poorly drained | Not reported |
| Hinckley | 5.7% | Excessively drained | 4.6 |
| Plymouth | 4.9% | Excessively drained | 4.4 |
| Merrimac | 4.8% | Somewhat excessively drained | 5.1 |
| Deerfield | 4.5% | Moderately well drained | 5.1 |
| Swansea | 4.1% | Very poorly drained | Not reported |
| Woodbridge | 3.5% | Moderately well drained | 5.2 |
What this means
What the soils in Plymouth County mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Plymouth County is very strongly acidic: pH 4.8 (most land between 4.0 and 5.6). 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.
Sandy topsoil covers 50% of the land. 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 fine sandy loam (20% of the land).
32% of the land is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.
For your lawn and yard
39% of the land is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.
A seasonal high water table comes within 18 inches of the surface on 37% of the land, often in spring. Basements, sump pumps and lawns in low spots feel it first.
For a septic system
For conventional septic absorption fields, NRCS rates 94% of the land in Plymouth County very limited, 2% somewhat limited and <1% not limited (4% not rated, such as urban land, pits or water).
Statewide, 88% of the land is very limited, so Plymouth County is more restrictive than typical.
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 16% of the land (<1% occasional, 7% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Drainage
How long the soil stays wet
The most common drainage class is excessively drained (26%). 66% of the land is moderately well drained or better, compared with 72% across Massachusetts.
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| Excessively drained | 26.3% | 13.5% |
| Somewhat excessively drained | 5.8% | 10.4% |
| Well drained | 13.0% | 32.9% |
| Moderately well drained | 21.1% | 15.1% |
| Somewhat poorly drained | 0.0% | 0.0% |
| Poorly drained | 10.6% | 7.2% |
| Very poorly drained | 18.2% | 10.6% |
| Not rated | 4.9% | 10.2% |
Septic absorption fields
NRCS rating for conventional drain fields
The rating looks at the soil from 24 to 60 inches deep: permeability, depth to a seasonal water table or bedrock, flooding and slope. “Very limited” means at least one feature is unfavorable enough that a conventional field is hard to make work.
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| Not limited | 0.5% | 0.9% |
| Somewhat limited | 1.8% | 3.0% |
| Very limited | 94.1% | 87.7% |
| Not rated | 3.6% | 8.3% |
Rain, runoff and water table
Hydrologic soil group, flooding, seasonal water table
Hydrologic soil group
How fast rain soaks in when the soil is already wet. Group A soaks in fastest, D slowest.
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 39.3% | 24.5% |
| B: moderate infiltration | 7.6% | 13.1% |
| C: slow infiltration | 5.1% | 16.0% |
| D: very slow infiltration (clayey, shallow or wet) | 8.9% | 16.3% |
| A/D: D as is, A if drained | 8.3% | 3.4% |
| B/D: D as is, B if drained | 14.5% | 8.0% |
| C/D: D as is, C if drained | 12.1% | 10.2% |
| Not rated | 4.4% | 8.6% |
Flooding
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| No flooding | 81.0% | 87.7% |
| Rare or very rare | 9.0% | 4.5% |
| Occasional | 0.1% | 0.7% |
| Frequent or very frequent | 6.5% | 2.6% |
| Not reported | 3.5% | 4.4% |
Seasonal high water table
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| Within 18 inches at some time of year | 36.6% | 24.6% |
| 18 inches to 3.3 feet | 19.6% | 19.7% |
| Deeper than 3.3 feet or none reported | 40.3% | 54.8% |
| Not reported | 3.5% | 1.0% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 4.8 (very strongly acidic); 80% of rated land falls between 4.0 and 5.6. Median topsoil organic matter is 4%.
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| Strongly acidic (below 5.5) | 71.4% | 61.0% |
| Moderately to slightly acidic (5.5–6.4) | 12.7% | 17.6% |
| Near neutral (6.5–7.3) | 0.1% | 1.3% |
| Alkaline (7.4 and up) | 0.0% | 0.1% |
| Not reported | 15.7% | 20.0% |
Texture
Show as a table
| Category | Plymouth County | Massachusetts |
|---|---|---|
| Sandy | 50.0% | 20.2% |
| Loamy (loam, silt loam and similar) | 34.3% | 58.3% |
| Clayey (40%+ clay) | 0.0% | 0.0% |
| Organic (muck or peat) | 11.6% | 10.9% |
| Not reported (rock, urban land, etc.) | 4.2% | 10.6% |
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
- Plymouth County, Massachusetts (FIPS 25023): 418,393 acres of mapped land, 40,169 acres of open water excluded. State comparisons pool all mapped land in Massachusetts.
- 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.