County soil summary
Soil types in Johnston County, North Carolina
The most widespread soils are Norfolk, Gilead and Goldsboro; the most common drainage class is well drained (47% of the land), and typical topsoil pH is 5.0.
- Well or moderately well drained
- 67% of land · state 68%
- Typical topsoil pH
- 5.0 very strongly acidic · state 5.2
- Septic fields very limited
- 68% of land · state 76%
- Subject to flooding
- 20% of land, any frequency · state 18%
Most common soils in Johnston County
Share of mapped land
A county is a patchwork of many soils. These 8 cover 53% of the mapped land; 53 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| Norfolk | 11.3% | Well drained | 4.8 |
| Gilead | 8.4% | Moderately well drained | 5.5 |
| Goldsboro | 7.5% | Moderately well drained | 4.7 |
| Rains | 7.1% | Poorly drained | 5.1 |
| Wehadkee | 5.5% | Poorly drained | 5.5 |
| Bibb | 5.2% | Poorly drained | 4.6 |
| Cecil | 4.2% | Well drained | 5.5 |
| Marlboro | 4.1% | Well drained | 5.8 |
What this means
What the soils in Johnston County mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Johnston County is very strongly acidic: pH 5.0 (most land between 4.5 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 59% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is sandy loam (41% of the land).
67% of the land is moderately well to excessively drained, which suits most garden plants.
For your lawn and yard
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 31% 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 68% of the land in Johnston County very limited, 32% somewhat limited and 0% not limited.
Statewide, 76% of the land is very limited, so Johnston County is less 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 20% of the land (5% occasional, 14% 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 well drained (47%). 67% of the land is moderately well drained or better, compared with 68% across North Carolina.
Show as a table
| Category | Johnston County | North Carolina |
|---|---|---|
| Excessively drained | 0.2% | 1.0% |
| Somewhat excessively drained | 0.2% | 2.8% |
| Well drained | 47.0% | 54.2% |
| Moderately well drained | 19.7% | 10.4% |
| Somewhat poorly drained | 6.2% | 5.4% |
| Poorly drained | 24.4% | 12.4% |
| Very poorly drained | 1.8% | 11.6% |
| Not rated | 0.5% | 2.3% |
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 | Johnston County | North Carolina |
|---|---|---|
| Not limited | 0.0% | 0.0% |
| Somewhat limited | 32.1% | 21.4% |
| Very limited | 67.5% | 76.4% |
| Not rated | 0.5% | 2.2% |
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 | Johnston County | North Carolina |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 6.4% | 11.8% |
| B: moderate infiltration | 44.0% | 35.7% |
| C: slow infiltration | 18.5% | 14.5% |
| D: very slow infiltration (clayey, shallow or wet) | 1.7% | 7.4% |
| A/D: D as is, A if drained | 11.9% | 10.6% |
| B/D: D as is, B if drained | 12.2% | 11.1% |
| C/D: D as is, C if drained | 4.9% | 7.1% |
| Not rated | 0.5% | 1.8% |
Flooding
Show as a table
| Category | Johnston County | North Carolina |
|---|---|---|
| No flooding | 80.3% | 81.9% |
| Rare or very rare | 1.4% | 7.5% |
| Occasional | 4.6% | 1.5% |
| Frequent or very frequent | 13.7% | 8.9% |
| Not reported | 0.0% | 0.2% |
Seasonal high water table
Show as a table
| Category | Johnston County | North Carolina |
|---|---|---|
| Within 18 inches at some time of year | 30.5% | 29.5% |
| 18 inches to 3.3 feet | 19.9% | 11.3% |
| Deeper than 3.3 feet or none reported | 49.6% | 59.0% |
| Not reported | 0.0% | 0.2% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 5.0 (very strongly acidic); 80% of rated land falls between 4.5 and 5.5. Median topsoil organic matter is 1.5%.
Show as a table
| Category | Johnston County | North Carolina |
|---|---|---|
| Strongly acidic (below 5.5) | 71.2% | 61.7% |
| Moderately to slightly acidic (5.5–6.4) | 28.3% | 33.5% |
| Near neutral (6.5–7.3) | 0.0% | 2.3% |
| Alkaline (7.4 and up) | 0.0% | 0.2% |
| Not reported | 0.5% | 2.3% |
Texture
Show as a table
| Category | Johnston County | North Carolina |
|---|---|---|
| Sandy | 40.6% | 24.0% |
| Loamy (loam, silt loam and similar) | 58.9% | 69.0% |
| Clayey (40%+ clay) | 0.0% | 0.0% |
| Organic (muck or peat) | 0.0% | 5.1% |
| Not reported (rock, urban land, etc.) | 0.5% | 1.8% |
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
- Johnston County, North Carolina (FIPS 37101): 462,276 acres of mapped land, 4,342 acres of open water excluded. State comparisons pool all mapped land in North Carolina.
- 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.