Sanilac County, Michigan
A shallow water table limits basements on 78% of Sanilac County's mapped land, a higher share than 87% of US counties. Shrink-swell clay limits houses without basements on 1%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list no flood losses here since 2016. 63% of homes were built before 1980, against 50% nationally; the median home dates from 1971.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Sanilac County
| Expansive clay (limits slab homes) | 0.8% |
| High water table (limits basements) | 78.2% |
| Septic fields very limited | 88.7% |
| Clay swell (LEP, by area) | 2.8% |
| High-swell land (LEP 6%+) | 0.1% |
| Mapped soil | 617,216 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Parkhill | 33% | n/a |
| Guelph | 10% | n/a |
| Conover | 10% | n/a |
| Londo | 4% | n/a |
| Marlette | 4% | n/a |
| Iosco | 3% | n/a |
How we count · survey areas MI151 (2025-09-04)
What the numbers mean here
On 78% of Sanilac 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: 33.37 in, 0.58 in above the 1991-2020 average year of 32.79 in.
USDA rates 89% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 21 of the last 52 weeks; the most was 27.2% of its area, on the October 14, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Sanilac County since 2016.
Rain
| Average year, 1991-2020 | 32.79 in |
| 12 months to August 2026 | 33.37 in (+0.58) |
| 2025 | 30.25 in (-2.54) |
| Wettest year since 1895 | 1996: 40.98 in |
| Driest year since 1895 | 1963: 20.42 in |
| Days with 1 inch or more, normal at YALE 1 NNW (22 mi away) | 5.4 |
Homes
| Housing units | 21,756 |
| Median year built | 1971 |
| Built before 1980 | 63% |
| Built 2000 or later | 14% |
| Owner-occupied | 83% |
| Median value, owner-occupied | $168,300 |
| Single-family detached | 82% |
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 |
|---|---|---|---|
| Huron County, MI | 33 mi | 0% | 93% |
| St. Clair County, MI | 36 mi | 23% | 90% |
| Lapeer County, MI | 38 mi | 4% | 60% |
| Tuscola County, MI | 40 mi | under 1% | 84% |
| Macomb County, MI | 55 mi | 9% | 80% |
| Genesee County, MI | 61 mi | under 1% | 72% |
| Oakland County, MI | 66 mi | 1% | 34% |
| Arenac County, MI | 68 mi | 6% | 76% |
Sources: USDA SSURGO (September 4, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status