Oakland County, Michigan
A shallow water table limits basements on 34% of Oakland County's mapped land, a higher share than 53% of US counties. Shrink-swell clay limits houses without basements on 1%.
40.7% of the county is in drought on the September 22, 2026 Drought Monitor map. FEMA's flood data list 140 flood losses here since 2016, 42% of them in buildings with basements. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1975.
Data as of September 22, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, September 22, 2026
of homes built before 1980
Soil under Oakland County
| Expansive clay (limits slab homes) | 1.4% |
| High water table (limits basements) | 34.0% |
| Septic fields very limited | 75.3% |
| Clay swell (LEP, by area) | 2.3% |
| High-swell land (LEP 6%+) | 0.7% |
| Urban land, not rated | 11.3% |
| Mapped soil | 580,723 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Marlette | 13% | n/a |
| Spinks | 7% | n/a |
| Riddles | 6% | n/a |
| Fox | 6% | 1% |
| Houghton | 5% | n/a |
| Oshtemo | 5% | 0% |
How we count · survey areas MI125 (2025-09-04)
What the numbers mean here
On 34% of Oakland County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 30.38 in, 2.87 in below the 1991-2020 average year of 33.25 in.
USDA rates 75% of the land very limited for septic absorption fields.
Drought
40.7% of the county is in drought (D1 or worse) on the September 22, 2026 map. Part of the county was in drought in 23 of the last 52 weeks; the most was 100% of its area, in 2 weeks, most recently on the October 21, 2025 map.
| Category, September 22, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 40.7% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
140 flood losses since 2016, $2.4 million paid. The worst year was 2021, with 34. Foundations of the buildings, where recorded: 42% basements, 27% slabs, 9% crawl spaces, 21% elevated. Median water depth outside the building: 5 in.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 5 |
| 2018 | 11 |
| 2019 | 12 |
| 2020 | 6 |
| 2021 | 34 |
| 2022 | 16 |
| 2023 | 33 |
| 2024 | 10 |
| 2025 | 6 |
| 2026 to date | 5 |
Rain
| Average year, 1991-2020 | 33.25 in |
| 12 months to August 2026 | 30.38 in (-2.87) |
| 2025 | 29.83 in (-3.42) |
| Wettest year since 1895 | 2011: 45.21 in |
| Driest year since 1895 | 1934: 20.86 in |
| Days with 1 inch or more, normal at DEARBORN (25 mi away) | 6.7 |
Homes
| Housing units | 561,348 |
| Median year built | 1975 |
| Built before 1980 | 58% |
| Built 2000 or later | 16% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $343,600 |
| Single-family detached | 68% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Macomb County, MI | 24 mi | 9% | 80% |
| Wayne County, MI | 27 mi | 6% | 66% |
| Livingston County, MI | 27 mi | under 1% | 37% |
| Genesee County, MI | 30 mi | under 1% | 72% |
| Lapeer County, MI | 31 mi | 4% | 60% |
| Washtenaw County, MI | 37 mi | 7% | 54% |
| St. Clair County, MI | 41 mi | 23% | 90% |
| Shiawassee County, MI | 44 mi | 0% | 80% |
Sources: USDA SSURGO (September 4, 2025) · US Drought Monitor (September 22, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status