Martin County, Minnesota
A shallow water table limits basements on 87% of Martin County's mapped land, a higher share than 94% of US counties. Shrink-swell clay limits houses without basements on 9%.
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. 77% of homes were built before 1980, against 50% nationally; the median home dates from 1960.
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 Martin County
| Expansive clay (limits slab homes) | 8.8% |
| High water table (limits basements) | 87.1% |
| Septic fields very limited | 88.7% |
| Clay swell (LEP, by area) | 3.8% |
| High-swell land (LEP 6%+) | 3.1% |
| Mapped soil | 467,000 acres |
How we count · survey areas MN091 (2025-09-10)
What the numbers mean here
On 87% of Martin 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: 22.56 in, 9.26 in below the 1991-2020 average year of 31.82 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 17 of the last 52 weeks; the most was 99.2% of its area, in 3 weeks, most recently on the March 31, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 4.3% |
| 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 Martin County since 2016.
Rain
| Average year, 1991-2020 | 31.82 in |
| 12 months to August 2026 | 22.56 in (-9.26) |
| 2025 | 30.26 in (-1.56) |
| Wettest year since 1895 | 2018: 46.17 in |
| Driest year since 1895 | 1910: 16.39 in |
| Days with 1 inch or more, normal at SWEA CITY 5N (20 mi away) | 7.7 |
Homes
| Housing units | 9,729 |
| Median year built | 1960 |
| Built before 1980 | 77% |
| Built 2000 or later | 9% |
| Owner-occupied | 69% |
| Median value, owner-occupied | $163,500 |
| Single-family detached | 76% |
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 |
|---|---|---|---|
| Watonwan County, MN | 21 mi | 12% | 87% |
| Emmet County, IA | 22 mi | 10% | 84% |
| Faribault County, MN | 30 mi | 37% | 88% |
| Jackson County, MN | 30 mi | 25% | 85% |
| Blue Earth County, MN | 34 mi | 40% | 84% |
| Kossuth County, IA | 36 mi | 18% | 90% |
| Dickinson County, IA | 38 mi | 10% | 75% |
| Cottonwood County, MN | 39 mi | 8% | 86% |
Sources: USDA SSURGO (September 10, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status