Tulsa County, Oklahoma
A shallow water table limits basements on 52% of Tulsa County's mapped land, a higher share than 68% of US counties and the 5th highest of 77 Oklahoma counties. Shrink-swell clay limits houses without basements on 47%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 264 flood losses here since 2016, 5% of them in buildings with basements. 52% of homes were built before 1980, against 50% nationally; the median home dates from 1979.
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 Tulsa County
| Expansive clay (limits slab homes) | 46.9% |
| High water table (limits basements) | 52.3% |
| Septic fields very limited | 83.9% |
| Clay swell (LEP, by area) | 5.0% |
| High-swell land (LEP 6%+) | 35.3% |
| Urban land, not rated | 5.3% |
| Mapped soil | 375,674 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Dennis | 21% | 100% |
| Radley | 6% | n/a |
| Okemah | 6% | n/a |
| Coweta | 5% | n/a |
| Wynona | 4% | n/a |
| Eram | 4% | n/a |
How we count · survey areas OK143 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 5.0% by land area here, and 35% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 47% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 47% of Tulsa County's mapped land has shrink-swell clay.
On 52% of Tulsa County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 40.51 in, 1.34 in below the 1991-2020 average year of 41.85 in.
USDA rates 84% of the land very limited for septic absorption fields.
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 33 of the last 52 weeks; the most was 100% of its area, in 25 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 | 41.9% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
264 flood losses since 2016, $20.6 million paid. The worst year was 2019, with 208. Foundations of the buildings, where recorded: 5% basements, 79% slabs, 6% crawl spaces, 10% elevated. Median water depth outside the building: 25 in.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 4 |
| 2018 | 3 |
| 2019 | 208 |
| 2020 | 1 |
| 2021 | 8 |
| 2022 | 20 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 7 |
| 2026 to date | 10 |
Rain
| Average year, 1991-2020 | 41.85 in |
| 12 months to August 2026 | 40.51 in (-1.34) |
| 2025 | 51.33 in (+9.48) |
| Wettest year since 1895 | 2019: 60.55 in |
| Driest year since 1895 | 1901: 21.39 in |
| Days with 1 inch or more, normal at TULSA INTL AP (6 mi away) | 12.3 |
Homes
| Housing units | 297,882 |
| Median year built | 1979 |
| Built before 1980 | 52% |
| Built 2000 or later | 24% |
| Owner-occupied | 60% |
| Median value, owner-occupied | $230,400 |
| Single-family detached | 69% |
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 |
|---|---|---|---|
| Rogers County, OK | 26 mi | 38% | 42% |
| Wagoner County, OK | 26 mi | 34% | 48% |
| Creek County, OK | 29 mi | 27% | 38% |
| Okmulgee County, OK | 33 mi | 37% | 53% |
| Washington County, OK | 40 mi | 52% | 55% |
| Mayes County, OK | 41 mi | 31% | 44% |
| Osage County, OK | 43 mi | 41% | 40% |
| Pawnee County, OK | 44 mi | 33% | 22% |
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