Soil series profile
Brookston soil series
Brookston is a poorly drained soil with a silty clay loam surface, mapped on 641,641 acres in 93 counties across 4 states. Hydrologic group B/D.
- Drainage class
- Poorly drained 92% of mapped acres
- Hydrologic group
- B/D 75% of mapped acres
- Typical topsoil pH
- 6.5 slightly acidic · range 6.5–6.7
- Mapped area
- 642k acres in 93 counties, 4 states
Typical Brookston profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–16 in (Ap) | Silty clay loam | 6.5 | 28% | 13% | 4% |
| 16–32 in (Btg1) | Silty clay loam | 7.0 | 34% | 19% | 1.25% |
| 32–44 in (Btg2) | Loam | 7.2 | 25% | 34% | 1.25% |
| 44–60 in (C) | Loam | 7.9 | 15% | 36% | 0.75% |

What this means
What Brookston soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Brookston soils is slightly acidic: pH 6.5 (most land between 6.5 and 6.7), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Brookston acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silty clay loam (48% of mapped Brookston acres).
>99% of mapped Brookston acres 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 >99% of mapped acres, 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 >99% of mapped acres, 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 >99% of the acres in mapped Brookston soils very limited, 0% somewhat limited and 0% not 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.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Brookston soil is found
Mapped acres
Brookston is mapped in Indiana, Michigan, Wisconsin and Ohio. The 60 counties with the most Brookston acres:
| County | Acres | Share of county land |
|---|---|---|
| Hancock County, IN | 59,000 | 30.2% |
| Shiawassee County, MI | 55,326 | 16.1% |
| Hamilton County, IN | 47,053 | 18.7% |
| Shelby County, IN | 42,925 | 16.5% |
| Madison County, IN | 33,132 | 11.5% |
| Johnson County, IN | 31,334 | 15.4% |
| Genesee County, MI | 28,058 | 6.9% |
| Howard County, IN | 27,218 | 14.6% |
| Pulaski County, IN | 24,822 | 9.0% |
| St. Joseph County, IN | 20,760 | 7.1% |
| Marion County, IN | 19,266 | 7.8% |
| Elkhart County, IN | 19,045 | 6.4% |
| Marshall County, IN | 18,943 | 6.7% |
| Lapeer County, MI | 15,474 | 3.7% |
| Ingham County, MI | 15,030 | 4.2% |
| Washtenaw County, MI | 14,145 | 3.1% |
| Noble County, IN | 11,925 | 4.6% |
| Oakland County, MI | 10,138 | 1.8% |
| Lenawee County, MI | 10,088 | 2.1% |
| Livingston County, MI | 9,363 | 2.6% |
| Hendricks County, IN | 8,520 | 3.3% |
| Wabash County, IN | 7,639 | 2.9% |
| Fond du Lac County, WI | 6,886 | 1.5% |
| Fayette County, IN | 6,714 | 4.9% |
| Washington County, WI | 5,498 | 2.0% |
| Steuben County, IN | 5,213 | 2.7% |
| Waukesha County, WI | 4,801 | 1.4% |
| Kosciusko County, IN | 4,429 | 1.3% |
| Miami County, IN | 4,228 | 1.8% |
| Saginaw County, MI | 4,120 | 0.8% |
| St. Clair County, MI | 4,107 | 0.9% |
| Allegan County, MI | 3,787 | 0.7% |
| Manitowoc County, WI | 3,416 | 0.9% |
| Union County, IN | 3,345 | 3.3% |
| Jasper County, IN | 3,312 | 0.9% |
| Montgomery County, OH | 3,254 | 1.1% |
| Darke County, OH | 3,243 | 0.8% |
| Dodge County, WI | 3,226 | 0.6% |
| Monroe County, MI | 3,222 | 0.9% |
| Fayette County, OH | 3,092 | 1.2% |
| Preble County, OH | 2,311 | 0.9% |
| Fulton County, IN | 2,265 | 1.0% |
| Rock County, WI | 2,211 | 0.5% |
| Miami County, OH | 2,175 | 0.8% |
| Greene County, OH | 2,168 | 0.8% |
| Ross County, OH | 2,051 | 0.5% |
| Hillsdale County, MI | 1,995 | 0.5% |
| White County, IN | 1,815 | 0.6% |
| Champaign County, OH | 1,523 | 0.6% |
| Clark County, OH | 1,475 | 0.6% |
| Logan County, OH | 1,290 | 0.4% |
| Calumet County, WI | 1,169 | 0.6% |
| Ozaukee County, WI | 1,009 | 0.7% |
| Morgan County, IN | 1,008 | 0.4% |
| Pickaway County, OH | 993 | 0.3% |
| Ionia County, MI | 960 | 0.3% |
| Franklin County, OH | 873 | 0.3% |
| Clinton County, OH | 869 | 0.3% |
| Wayne County, IN | 819 | 0.3% |
| Highland County, OH | 743 | 0.2% |
Septic absorption fields
NRCS rating, share of Brookston acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 99.8% |
| Not rated | 0.2% |
Drainage, water table and flooding
Share of Brookston acres
- Depth to seasonal high water table
- About 6 inches (median where reported); within 18 inches on >99% of acres.
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 0–1% (median 1%).
- Topsoil organic matter
- Median 4%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 0.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 92.4% |
| Very poorly drained | 7.4% |
| Not rated | 0.2% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 0.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 75.0% |
| C/D: D as is, C if drained | 24.8% |
| Not rated | 0.2% |
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
- All map unit components named Brookston (component kind "Series") in SSURGO: 641,641 acres.
- Method
- Shares are by mapped acres of Brookston components. The profile comes from the single largest Brookston component. Full methodology.