HomeNorth DakotaDunn County
Dunn County, North Dakota
Shrink-swell clay limits houses without basements on 22% of Dunn County's mapped land, a higher share than 73% of US counties. A shallow water table limits basements on 5%.
99.8% 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. 45% of homes were built before 1980, against 50% nationally; the median home dates from 1983.
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 Dunn County
| Expansive clay (limits slab homes) | 22.3% |
| High water table (limits basements) | 4.7% |
| Septic fields very limited | 81.9% |
| Clay swell (LEP, by area) | 3.9% |
| High-swell land (LEP 6%+) | 23.7% |
| Mapped soil | 1,332,600 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Vebar | 6% | n/a |
| Cabba | 6% | n/a |
| Amor | 4% | n/a |
| Rhoades | 4% | n/a |
| Arikara | 3% | n/a |
| Chama | 3% | n/a |
How we count · survey areas ND025 (2026-05-04)
What the numbers mean here
Clay swell averages a linear extensibility of 3.9% by land area here, and 24% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 22% of the mapped land.
Clay shrinks as it dries: 99.8% of the county is in drought on the latest map, and 22% of Dunn County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 14.26 in, 3.04 in below the 1991-2020 average year of 17.30 in.
USDA rates 82% of the land very limited for septic absorption fields.
Drought
99.8% 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, in 8 weeks, most recently on the September 22, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 99.8% |
| D2 severe or worse | 82.9% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Dunn County since 2016.
Rain
| Average year, 1991-2020 | 17.30 in |
| 12 months to August 2026 | 14.26 in (-3.04) |
| 2025 | 20.14 in (+2.84) |
| Wettest year since 1895 | 2013: 25.26 in |
| Driest year since 1895 | 1934: 6.72 in |
| Days with 1 inch or more, normal at DICKINSON RCH HQ (15 mi away) | 3.1 |
Homes
| Housing units | 2,088 |
| Median year built | 1983 |
| Built before 1980 | 45% |
| Built 2000 or later | 33% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $275,000 |
| 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 |
|---|---|---|---|
| Mercer County, ND | 37 mi | 15% | 4% |
| Stark County, ND | 37 mi | 37% | 4% |
| Billings County, ND | 43 mi | 25% | 4% |
| McKenzie County, ND | 46 mi | 16% | 4% |
| McLean County, ND | 59 mi | 9% | 13% |
| Mountrail County, ND | 60 mi | 12% | 15% |
| Oliver County, ND | 62 mi | 13% | 5% |
| Hettinger County, ND | 64 mi | 43% | 7% |
Sources: USDA SSURGO (May 4, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status