Smith County, Tennessee
Shrink-swell clay limits houses without basements on 41% of Smith County's mapped land, a higher share than 87% of US counties and the 2nd highest of 95 Tennessee counties. A shallow water table limits basements on 3%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 33 flood losses here since 2016. 43% of homes were built before 1980, against 50% nationally; the median home dates from 1988.
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 Smith County
| Expansive clay (limits slab homes) | 40.6% |
| High water table (limits basements) | 3.2% |
| Septic fields very limited | 84.8% |
| Clay swell (LEP, by area) | 6.2% |
| High-swell land (LEP 6%+) | 46.1% |
| Mapped soil | 208,400 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Ashwood | 18% | n/a |
| Mimosa | 18% | n/a |
| Dellrose | 9% | n/a |
| Hawthorne | 7% | n/a |
| Armour | 6% | n/a |
| Talbott | 5% | n/a |
How we count · survey areas TN159 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 6.2% by land area here, and 46% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 41% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 41% of Smith County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 44.47 in, 9.58 in below the 1991-2020 average year of 54.05 in.
USDA rates 85% 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 19 of the last 52 weeks; the most was 100% of its area, in 15 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% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
33 flood losses since 2016, $425,839 paid. The worst year was 2021, with 12. Median water depth outside the building: 22.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 8 |
| 2018 | 2 |
| 2019 | 5 |
| 2020 | 4 |
| 2021 | 12 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 2 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 54.05 in |
| 12 months to August 2026 | 44.47 in (-9.58) |
| 2025 | 50.72 in (-3.33) |
| Wettest year since 1895 | 1979: 70.41 in |
| Driest year since 1895 | 2007: 35.67 in |
| Days with 1 inch or more, normal at CARTHAGE (2 mi away) | 17.7 |
Homes
| Housing units | 8,752 |
| Median year built | 1988 |
| Built before 1980 | 43% |
| Built 2000 or later | 26% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $243,800 |
| 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 |
|---|---|---|---|
| Trousdale County, TN | 15 mi | 44% | 10% |
| Jackson County, TN | 16 mi | 23% | 6% |
| Macon County, TN | 19 mi | 10% | 16% |
| DeKalb County, TN | 21 mi | 13% | 19% |
| Wilson County, TN | 21 mi | 16% | 14% |
| Putnam County, TN | 26 mi | 6% | 12% |
| Clay County, TN | 29 mi | 4% | 8% |
| Sumner County, TN | 31 mi | 18% | 19% |
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