State soil summary
Soil types in Alaska
The most widespread soil series in Alaska are Tatalina, Seventeenmile, Tolstoi. Pick a county below, or enter a ZIP code for the county you live in.
- Well or moderately well drained
- 35% of mapped land
- Typical topsoil pH
- 4.8 very strongly acidic · most land 3.9–6.5
- Septic fields very limited
- 88% 4% not limited
- Subject to flooding
- 12% of land, any frequency
Alaska counties
1 county reports, by population
| County | Most common soil | Well drained | Topsoil pH | Septic very limited |
|---|---|---|---|---|
| Anchorage Municipality | Deception | 49% | 5.5 | 80% |
What this means
What Alaska soils mean for gardens, lawns and septic systems
For gardens
Typical topsoil in Alaska is very strongly acidic: pH 4.8 (most land between 3.9 and 6.5). 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 42% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is peat (29% of the land).
44% of the land is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.
For lawns and yards
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.
A seasonal high water table comes within 18 inches of the surface on 44% 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 88% of the land in Alaska very limited, 3% somewhat limited and 4% not limited (5% 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 12% of the land (3% occasional, 8% 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 | 0.2% |
| Somewhat excessively drained | 1.7% |
| Well drained | 29.6% |
| Moderately well drained | 3.6% |
| Somewhat poorly drained | 6.1% |
| Poorly drained | 18.2% |
| Very poorly drained | 19.4% |
| Not rated | 21.1% |
Septic absorption fields
Show as a table
| Category | Share of land |
|---|---|
| Not limited | 4.3% |
| Somewhat limited | 2.5% |
| Very limited | 88.4% |
| Not rated | 4.8% |
Topsoil pH
Show as a table
| Category | Share of land |
|---|---|
| Strongly acidic (below 5.5) | 45.5% |
| Moderately to slightly acidic (5.5–6.4) | 13.4% |
| Near neutral (6.5–7.3) | 4.4% |
| Alkaline (7.4 and up) | 2.8% |
| Not reported | 33.9% |
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
- Alaska: 374,984,216 acres of mapped land in 28 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.