County soil summary
Soil types in Hawaii County, Hawaii
The most widespread soils are Kaiwiki, Keei and Honokaa; the most common drainage class is well drained (57% of the land), and typical topsoil pH is 6.0.
- Well or moderately well drained
- 87% of land · state 87%
- Typical topsoil pH
- 6.0 moderately acidic · state 6.0
- Septic fields very limited
- 95% of land · state 93%
- Subject to flooding
- 6% of land, any frequency · state 7%
Most common soils in Hawaii County
Share of mapped land
A county is a patchwork of many soils. These 8 cover 46% of the mapped land; 150 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| Lava flowsLand type, not a soil series | 32.8% | — | — |
| Kaiwiki | 2.6% | Well drained | 5.2 |
| Keei | 2.2% | Well drained | Not reported |
| Honokaa | 1.9% | Well drained | 6.0 |
| Waimea | 1.8% | Well drained | 7.0 |
| Keaukaha | 1.8% | Well drained | Not reported |
| Kekake | 1.6% | Moderately well drained | Not reported |
| Kemole | 1.6% | Well drained | 6.4 |
What this means
What the soils in Hawaii County mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Hawaii County is moderately acidic: pH 6.0 (most land between 4.8 and 7.0). Many vegetables grow well here, and some gardens benefit from a little lime. Test before adding any.
Loamy topsoil (loam, silt loam and similar) covers 60% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is bedrock (25% of the land).
87% of the land is moderately well to excessively drained, which suits most garden plants.
For your lawn and yard
On 52% of the land, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For a septic system
For conventional septic absorption fields, NRCS rates 95% of the land in Hawaii County very limited, 3% somewhat limited and <1% not limited (2% not rated, such as urban land, pits or water).
That is close to the state as a whole (93% very 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.
Flooding is mapped on 6% of the land (4% occasional, 0% 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 (57%). 87% of the land is moderately well drained or better, compared with 87% across Hawaii.
Show as a table
| Category | Hawaii County | Hawaii |
|---|---|---|
| Excessively drained | 18.4% | 13.2% |
| Somewhat excessively drained | 4.8% | 3.1% |
| Well drained | 57.1% | 65.8% |
| Moderately well drained | 6.9% | 4.6% |
| Somewhat poorly drained | 0.9% | 0.6% |
| Poorly drained | 0.5% | 1.9% |
| Very poorly drained | 1.0% | 0.9% |
| Not rated | 10.5% | 9.8% |
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 | Hawaii County | Hawaii |
|---|---|---|
| Not limited | 0.3% | 0.2% |
| Somewhat limited | 3.1% | 5.1% |
| Very limited | 94.9% | 93.1% |
| Not rated | 1.7% | 1.6% |
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 | Hawaii County | Hawaii |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 36.3% | 29.2% |
| B: moderate infiltration | 10.3% | 18.3% |
| C: slow infiltration | 25.7% | 30.0% |
| D: very slow infiltration (clayey, shallow or wet) | 24.1% | 18.6% |
| A/D: D as is, A if drained | 0.0% | 0.2% |
| B/D: D as is, B if drained | 1.0% | 0.7% |
| C/D: D as is, C if drained | 1.2% | 1.0% |
| Not rated | 1.4% | 2.0% |
Flooding
Show as a table
| Category | Hawaii County | Hawaii |
|---|---|---|
| No flooding | 9.9% | 38.2% |
| Rare or very rare | 1.6% | 2.5% |
| Occasional | 4.0% | 3.6% |
| Frequent or very frequent | 0.0% | 0.6% |
| Not reported | 84.5% | 55.1% |
Seasonal high water table
Show as a table
| Category | Hawaii County | Hawaii |
|---|---|---|
| Within 18 inches at some time of year | 4.0% | 4.0% |
| 18 inches to 3.3 feet | 0.0% | 0.2% |
| Deeper than 3.3 feet or none reported | 11.5% | 40.8% |
| Not reported | 84.5% | 55.1% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 6.0 (moderately acidic); 80% of rated land falls between 4.8 and 7.0. Median topsoil organic matter is 9%.
Show as a table
| Category | Hawaii County | Hawaii |
|---|---|---|
| Strongly acidic (below 5.5) | 20.8% | 26.3% |
| Moderately to slightly acidic (5.5–6.4) | 21.2% | 20.5% |
| Near neutral (6.5–7.3) | 28.8% | 29.3% |
| Alkaline (7.4 and up) | 1.2% | 1.7% |
| Not reported | 27.9% | 22.3% |
Texture
Show as a table
| Category | Hawaii County | Hawaii |
|---|---|---|
| Sandy | 9.5% | 6.9% |
| Loamy (loam, silt loam and similar) | 60.2% | 59.0% |
| Clayey (40%+ clay) | 0.7% | 13.8% |
| Organic (muck or peat) | 1.2% | 1.6% |
| Not reported (rock, urban land, etc.) | 28.4% | 18.7% |
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
- Hawaii County, Hawaii (FIPS 15001): 2,579,828 acres of mapped land, 207 acres of open water excluded. State comparisons pool all mapped land in Hawaii.
- 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.