County soil summary
Soil types in Milwaukee County, Wisconsin
The most widespread soils are Ozaukee, Blount and Mequon; the most common drainage class is moderately well drained (25% of the land), and typical topsoil pH is 6.7.
- Well or moderately well drained
- 31% of land · state 65%
- Typical topsoil pH
- 6.7 neutral · state 5.9
- Septic fields very limited
- 61% of land · state 92%
- Subject to flooding
- 2% of land, any frequency · state 7%
Most common soils in Milwaukee County
Share of mapped land
A county is a patchwork of many soils. These 8 cover 84% of the mapped land; 61 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| NotcomGeneral soil group, not a named series | 34.9% | — | — |
| Ozaukee | 24.4% | Moderately well drained | 6.6 |
| Blount | 6.2% | Somewhat poorly drained | 6.4 |
| Mequon | 5.7% | Somewhat poorly drained | 7.0 |
| Ashkum | 4.5% | Poorly drained | 7.0 |
| Clayey landLand type, not a soil series | 4.1% | — | — |
| Kewaunee | 2.3% | Well drained | 6.5 |
| Loamy landLand type, not a soil series | 1.9% | — | — |
What this means
What the soils in Milwaukee County mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Milwaukee County is neutral: pH 6.7 (most land between 6.2 and 7.0), the range most vegetables, flowers and lawn grasses prefer.
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 silt loam (46% of the land).
For your lawn and yard
On 57% 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 61% of the land in Milwaukee County very limited, <1% somewhat limited and 0% not limited (39% not rated, such as urban land, pits or water).
Statewide, 92% of the land is very limited, so Milwaukee 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.
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 moderately well drained (25%). 31% of the land is moderately well drained or better, compared with 65% across Wisconsin.
Show as a table
| Category | Milwaukee County | Wisconsin |
|---|---|---|
| Excessively drained | 0.0% | 8.5% |
| Somewhat excessively drained | 0.5% | 5.1% |
| Well drained | 5.7% | 36.1% |
| Moderately well drained | 24.8% | 15.1% |
| Somewhat poorly drained | 17.3% | 14.3% |
| Poorly drained | 7.6% | 7.4% |
| Very poorly drained | 2.1% | 11.3% |
| Not rated | 42.2% | 2.2% |
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 | Milwaukee County | Wisconsin |
|---|---|---|
| Not limited | 0.0% | 0.0% |
| Somewhat limited | 0.5% | 4.9% |
| Very limited | 60.8% | 91.9% |
| Not rated | 38.7% | 3.2% |
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 | Milwaukee County | Wisconsin |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% | 19.7% |
| B: moderate infiltration | 1.4% | 19.8% |
| C: slow infiltration | 33.3% | 16.5% |
| D: very slow infiltration (clayey, shallow or wet) | 7.8% | 6.2% |
| A/D: D as is, A if drained | 0.5% | 10.7% |
| B/D: D as is, B if drained | 2.7% | 10.3% |
| C/D: D as is, C if drained | 12.5% | 13.3% |
| Not rated | 41.8% | 3.5% |
Flooding
Show as a table
| Category | Milwaukee County | Wisconsin |
|---|---|---|
| No flooding | 61.7% | 91.3% |
| Rare or very rare | 0.0% | 0.4% |
| Occasional | 0.3% | 2.4% |
| Frequent or very frequent | 1.8% | 3.7% |
| Not reported | 36.2% | 2.2% |
Seasonal high water table
Show as a table
| Category | Milwaukee County | Wisconsin |
|---|---|---|
| Within 18 inches at some time of year | 19.3% | 36.9% |
| 18 inches to 3.3 feet | 32.5% | 8.0% |
| Deeper than 3.3 feet or none reported | 12.0% | 53.1% |
| Not reported | 36.2% | 2.0% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 6.7 (neutral); 80% of rated land falls between 6.2 and 7.0. Median topsoil organic matter is 2%.
Show as a table
| Category | Milwaukee County | Wisconsin |
|---|---|---|
| Strongly acidic (below 5.5) | 0.0% | 18.5% |
| Moderately to slightly acidic (5.5–6.4) | 16.0% | 43.9% |
| Near neutral (6.5–7.3) | 43.5% | 26.0% |
| Alkaline (7.4 and up) | 0.8% | 0.5% |
| Not reported | 39.7% | 11.1% |
Texture
Show as a table
| Category | Milwaukee County | Wisconsin |
|---|---|---|
| Sandy | 0.2% | 17.8% |
| Loamy (loam, silt loam and similar) | 59.9% | 66.3% |
| Clayey (40%+ clay) | 0.3% | 0.5% |
| Organic (muck or peat) | 0.9% | 12.1% |
| Not reported (rock, urban land, etc.) | 38.7% | 3.4% |
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
- Milwaukee County, Wisconsin (FIPS 55079): 154,191 acres of mapped land, 1,233 acres of open water excluded. State comparisons pool all mapped land in Wisconsin.
- 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.