Dawson County, Montana
USDA's soil survey flags shrink-swell clay on 8% of Dawson County's mapped land and a shallow water table under basements on 1%, both below the national shares of 15% and 29%. 87.3% of the county is in drought on the October 13, 2026 Drought Monitor map.
FEMA's flood data list 2 flood losses here since 2016. 76% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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 Dawson County
| Expansive clay (limits slab homes) | 8.4% |
| High water table (limits basements) | 0.7% |
| Septic fields very limited | 78.8% |
| Clay swell (LEP, by area) | 3.5% |
| High-swell land (LEP 6%+) | 7.7% |
| Mapped soil | 1,523,848 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Lonna | 22% | n/a |
| Lambert | 14% | n/a |
| Cambeth | 8% | n/a |
| Dimyaw | 4% | n/a |
| Tinsley | 4% | n/a |
| Attewan | 3% | n/a |
How we count · survey areas MT021 (2025-08-27)
What the numbers mean here
Rain over the 12 months to August 2026: 11.01 in, 3.38 in below the 1991-2020 average year of 14.39 in.
USDA rates 79% of the land very limited for septic absorption fields.
With shrink-swell clay on 8% and a shallow water table on 1% of the land, the soil survey points to neither problem across most of Dawson County; conditions still vary lot by lot.
Drought
87.3% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 39 of the last 52 weeks; the most was 100% of its area, in 12 weeks, most recently on the August 11, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 99% |
| D1 moderate drought or worse | 87.3% |
| D2 severe or worse | 43.8% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $110,015 paid. The worst year was 2022, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 1 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 1 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 14.39 in |
| 12 months to August 2026 | 11.01 in (-3.38) |
| 2025 | 15.53 in (+1.14) |
| Wettest year since 1895 | 1906: 21.12 in |
| Driest year since 1895 | 1934: 5.34 in |
| Days with 1 inch or more, normal at LINDSAY (12 mi away) | 2 |
Homes
| Housing units | 4,381 |
| Median year built | 1966 |
| Built before 1980 | 76% |
| Built 2000 or later | 9% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $185,300 |
| Single-family detached | 71% |
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 |
|---|---|---|---|
| Wibaux County, MT | 36 mi | 22% | 2% |
| Richland County, MT | 39 mi | 8% | 2% |
| Prairie County, MT | 42 mi | 10% | 1% |
| McCone County, MT | 47 mi | 12% | under 1% |
| Golden Valley County, ND | 54 mi | 7% | 3% |
| Fallon County, MT | 69 mi | 21% | 1% |
| Roosevelt County, MT | 70 mi | 10% | 2% |
| Billings County, ND | 74 mi | 25% | 4% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status