Olmsted County, Minnesota
A shallow water table limits basements on 34% of Olmsted County's mapped land, a higher share than 53% of US counties. Shrink-swell clay limits houses without basements on 6%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 19 flood losses here since 2016. 41% of homes were built before 1980, against 50% nationally; the median home dates from 1989.
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 Olmsted County
| Expansive clay (limits slab homes) | 5.9% |
| High water table (limits basements) | 34.2% |
| Septic fields very limited | 91.7% |
| Clay swell (LEP, by area) | 3.8% |
| High-swell land (LEP 6%+) | 12.3% |
| Mapped soil | 419,600 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Downs | 16% | n/a |
| Tama | 7% | 0% |
| Racine | 3% | n/a |
| Rockton | 3% | n/a |
| Channahon | 3% | n/a |
| Garwin | 3% | n/a |
How we count · survey areas MN109 (2025-09-10)
What the numbers mean here
On 34% of Olmsted 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: 28.84 in, 6.95 in below the 1991-2020 average year of 35.79 in.
USDA rates 92% 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 16 of the last 52 weeks; the most was 100% of its area, on the June 23, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 38% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
19 flood losses since 2016, $718,786 paid. The worst year was 2019, with 13.
| Year | Flood losses |
|---|---|
| 2016 | 3 |
| 2017 | 0 |
| 2018 | 1 |
| 2019 | 13 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 35.79 in |
| 12 months to August 2026 | 28.84 in (-6.95) |
| 2025 | 34.18 in (-1.61) |
| Wettest year since 1895 | 2019: 50.75 in |
| Driest year since 1895 | 1910: 13.39 in |
| Days with 1 inch or more, normal at ROCHESTER INTL AP (8 mi away) | 7.6 |
Homes
| Housing units | 71,151 |
| Median year built | 1989 |
| Built before 1980 | 41% |
| Built 2000 or later | 35% |
| Owner-occupied | 71% |
| Median value, owner-occupied | $331,700 |
| Single-family detached | 64% |
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 |
|---|---|---|---|
| Wabasha County, MN | 22 mi | 6% | 36% |
| Dodge County, MN | 23 mi | 1% | 90% |
| Fillmore County, MN | 27 mi | 8% | 21% |
| Mower County, MN | 29 mi | 3% | 86% |
| Winona County, MN | 32 mi | 6% | 15% |
| Goodhue County, MN | 32 mi | 1% | 48% |
| Steele County, MN | 41 mi | 6% | 85% |
| Buffalo County, WI | 42 mi | 4% | 16% |
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