Harper County, Oklahoma
USDA's soil survey flags shrink-swell clay on 3% of Harper County's mapped land and a shallow water table under basements on 2%, 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. 79% of homes were built before 1980, against 50% nationally; the median home dates from 1965.
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 Harper County
| Expansive clay (limits slab homes) | 3.2% |
| High water table (limits basements) | 1.7% |
| Septic fields very limited | 69.9% |
| Clay swell (LEP, by area) | 2.2% |
| High-swell land (LEP 6%+) | 2.6% |
| Mapped soil | 664,858 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Quinlan | 13% | n/a |
| Selman | 12% | n/a |
| Woodward | 9% | n/a |
| St. Paul | 5% | n/a |
| Tivoli | 5% | n/a |
| Westola | 4% | n/a |
How we count · survey areas OK059 (2025-08-29)
What the numbers mean here
Rain over the 12 months to August 2026: 17.04 in, 6.18 in below the 1991-2020 average year of 23.22 in.
USDA rates 70% of the land very limited for septic absorption fields.
With shrink-swell clay on 3% and a shallow water table on 2% of the land, the soil survey points to neither problem across most of Harper 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 34 of the last 52 weeks; the most was 100% of its area, in 33 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 | 13.2% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Harper County since 2016.
Rain
| Average year, 1991-2020 | 23.22 in |
| 12 months to August 2026 | 17.04 in (-6.18) |
| 2025 | 27.23 in (+4.01) |
| Wettest year since 1895 | 1957: 39.56 in |
| Driest year since 1895 | 1954: 10.74 in |
| Days with 1 inch or more, normal at GATE (22 mi away) | 6 |
Homes
| Housing units | 1,714 |
| Median year built | 1965 |
| Built before 1980 | 79% |
| Built 2000 or later | 12% |
| Owner-occupied | 84% |
| Median value, owner-occupied | $99,200 |
| Single-family detached | 87% |
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 |
|---|---|---|---|
| Clark County, KS | 31 mi | 18% | 4% |
| Woodward County, OK | 34 mi | 8% | 6% |
| Comanche County, KS | 35 mi | 5% | 4% |
| Ellis County, OK | 40 mi | 3% | 4% |
| Woods County, OK | 45 mi | 13% | 8% |
| Beaver County, OK | 46 mi | 6% | 7% |
| Meade County, KS | 49 mi | 35% | 6% |
| Lipscomb County, TX | 49 mi | 7% | 1% |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status