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Franklin County, Washington
USDA's soil survey flags shrink-swell clay on 0% of Franklin County's mapped land and a shallow water table under basements on under 1%, 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. 37% of homes were built before 1980, against 50% nationally; the median home dates from 1997.
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 Franklin County
| Expansive clay (limits slab homes) | 0.0% |
| High water table (limits basements) | 0.5% |
| Septic fields very limited | 50.7% |
| Clay swell (LEP, by area) | 1.6% |
| High-swell land (LEP 6%+) | 0.0% |
| Mapped soil | 806,347 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Quincy | 19% | n/a |
| Ritzville | 18% | n/a |
| Sagehill | 8% | n/a |
| Shano | 5% | n/a |
| Warden | 5% | n/a |
| Roloff | 5% | n/a |
How we count · survey areas WA021 (2025-08-28)
What the numbers mean here
Rain over the 12 months to August 2026: 9.93 in, 0.29 in above the 1991-2020 average year of 9.64 in.
USDA rates 51% of the land very limited for septic absorption fields.
With shrink-swell clay on 0% and a shallow water table on under 1% of the land, the soil survey points to neither problem across most of Franklin 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 20 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 | 0.4% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Franklin County since 2016.
Rain
| Average year, 1991-2020 | 9.64 in |
| 12 months to August 2026 | 9.93 in (+0.29) |
| 2025 | 10.58 in (+0.94) |
| Wettest year since 1895 | 1996: 14.80 in |
| Driest year since 1895 | 1976: 5.20 in |
| Days with 1 inch or more, normal at ICE HARBOR DAM (20 mi away) | 0.2 |
Homes
| Housing units | 31,183 |
| Median year built | 1997 |
| Built before 1980 | 37% |
| Built 2000 or later | 47% |
| Owner-occupied | 71% |
| Median value, owner-occupied | $379,300 |
| Single-family detached | 74% |
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 |
|---|---|---|---|
| Walla Walla County, WA | 28 mi | 0% | 4% |
| Benton County, WA | 36 mi | 0% | 1% |
| Adams County, WA | 39 mi | under 1% | 2% |
| Columbia County, WA | 51 mi | under 1% | 4% |
| Grant County, WA | 54 mi | 0% | 2% |
| Garfield County, WA | 65 mi | 13% | 2% |
| Umatilla County, OR | 66 mi | 7% | 3% |
| Whitman County, WA | 70 mi | 1% | 15% |
Sources: USDA SSURGO (August 28, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status