Grant County, Oregon
USDA's soil survey flags shrink-swell clay on 15% of Grant County's mapped land and a shallow water table under basements on 4%, both below the national shares of 15% and 29%. 100% 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. 67% of homes were built before 1980, against 50% nationally; the median home dates from 1971.
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 Grant County
| Expansive clay (limits slab homes) | 14.5% |
| High water table (limits basements) | 3.5% |
| Septic fields very limited | 97.4% |
| Clay swell (LEP, by area) | 3.1% |
| High-swell land (LEP 6%+) | 13.8% |
| Mapped soil | 2,898,461 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Bocker | 3% | n/a |
| Keerins | 3% | n/a |
| Anatone | 2% | n/a |
| Rockly | 2% | n/a |
| Gwin | 2% | n/a |
| Porch | 2% | n/a |
What the numbers mean here
Rain over the 12 months to August 2026: 16.55 in, 4.25 in below the 1991-2020 average year of 20.80 in.
USDA rates 97% of the land very limited for septic absorption fields.
With shrink-swell clay on 15% and a shallow water table on 4% of the land, the soil survey points to neither problem across most of Grant County; conditions still vary lot by lot.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 26 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 100% |
| D3 extreme or worse | 97.7% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Grant County since 2016.
Rain
| Average year, 1991-2020 | 20.80 in |
| 12 months to August 2026 | 16.55 in (-4.25) |
| 2025 | 19.73 in (-1.07) |
| Wettest year since 1895 | 1983: 30.56 in |
| Driest year since 1895 | 1935: 12.62 in |
| Days with 1 inch or more, normal at JOHN DAY (6 mi away) | 0.1 |
Homes
| Housing units | 4,157 |
| Median year built | 1971 |
| Built before 1980 | 67% |
| Built 2000 or later | 15% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $229,700 |
| Single-family detached | 73% |
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 |
|---|---|---|---|
| Wheeler County, OR | 53 mi | 27% | 1% |
| Baker County, OR | 67 mi | 47% | 7% |
| Morrow County, OR | 70 mi | 7% | 1% |
| Crook County, OR | 71 mi | n/a | n/a |
| Union County, OR | 75 mi | 26% | 21% |
| Umatilla County, OR | 77 mi | 7% | 3% |
| Gilliam County, OR | 87 mi | 3% | under 1% |
| Harney County, OR | 99 mi | 34% | 15% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status