Ravalli County, Montana
USDA's soil survey flags shrink-swell clay on under 1% of Ravalli County's mapped land and a shallow water table under basements on 8%, both below the national shares of 15% and 29%. None 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. 39% of homes were built before 1980, against 50% nationally; the median home dates from 1991.
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 Ravalli County
| Expansive clay (limits slab homes) | 0.3% |
| High water table (limits basements) | 8.1% |
| Septic fields very limited | 84.5% |
| Clay swell (LEP, by area) | 1.2% |
| High-swell land (LEP 6%+) | 0.3% |
| Mapped soil | 1,533,693 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Chereete | 1% | n/a |
| Riverrun | 1% | n/a |
| Farnuf | 1% | n/a |
| Burnt Fork | 1% | n/a |
| Quast | 1% | n/a |
| Sheafman | 1% | n/a |
How we count · survey areas MT603 (2025-09-02), MT645 (2025-09-03), MT647 (2025-09-03)
What the numbers mean here
Rain over the 12 months to August 2026: 31.37 in, 2.18 in above the 1991-2020 average year of 29.19 in.
USDA rates 84% of the land very limited for septic absorption fields.
With shrink-swell clay on under 1% and a shallow water table on 8% of the land, the soil survey points to neither problem across most of Ravalli County; conditions still vary lot by lot.
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 13 of the last 52 weeks; the most was 100% of its area, in 9 weeks, most recently on the December 16, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $0 paid. The worst year was 2021, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 29.19 in |
| 12 months to August 2026 | 31.37 in (+2.18) |
| 2025 | 29.41 in (+0.22) |
| Wettest year since 1895 | 1927: 50.19 in |
| Driest year since 1895 | 1935: 14.40 in |
| Days with 1 inch or more, normal at WESTERN AG RSCH CTR (17 mi away) | 0.1 |
Homes
| Housing units | 21,179 |
| Median year built | 1991 |
| Built before 1980 | 39% |
| Built 2000 or later | 31% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $476,600 |
| Single-family detached | 80% |
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 |
|---|---|---|---|
| Granite County, MT | 39 mi | 6% | 7% |
| Deer Lodge County, MT | 46 mi | 6% | 10% |
| Missoula County, MT | 66 mi | 1% | 3% |
| Idaho County, ID | 67 mi | 9% | 12% |
| Silver Bow County, MT | 71 mi | 2% | 5% |
| Powell County, MT | 77 mi | 10% | 6% |
| Lemhi County, ID | 80 mi | 10% | 12% |
| Clearwater County, ID | 84 mi | 1% | 14% |
Sources: USDA SSURGO (September 3, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status