Sullivan County, Tennessee
USDA's soil survey flags shrink-swell clay on 0% of Sullivan County's mapped land and a shallow water table under basements on 8%, both below the national shares of 15% and 29%. None of the county is in drought on the October 13, 2026 Drought Monitor map.
FEMA's flood data list 44 flood losses here since 2016, 18% of them in buildings with basements. 55% of homes were built before 1980, against 50% nationally; the median home dates from 1977.
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 Sullivan County
| Expansive clay (limits slab homes) | 0.0% |
| High water table (limits basements) | 8.1% |
| Septic fields very limited | 81.7% |
| Clay swell (LEP, by area) | 2.3% |
| High-swell land (LEP 6%+) | 0.0% |
| Urban land, not rated | 3.3% |
| Mapped soil | 275,100 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Collegedale | 19% | n/a |
| Montevallo | 19% | n/a |
| Etowah | 10% | n/a |
| Talbott | 7% | n/a |
| Steadman | 6% | n/a |
| Bays | 5% | n/a |
How we count · survey areas TN163 (2025-08-29)
What the numbers mean here
Rain over the 12 months to August 2026: 42.78 in, 3.11 in below the 1991-2020 average year of 45.89 in.
USDA rates 82% of the land very limited for septic absorption fields.
With shrink-swell clay on 0% and a shallow water table on 8% of the land, the soil survey points to neither problem across most of Sullivan County; conditions still vary lot by lot.
Drought
0% 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 11 weeks, most recently on the June 23, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 12.2% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
44 flood losses since 2016, $669,093 paid. The worst year was 2020, with 14. Foundations of the buildings, where recorded: 18% basements, 14% slabs, 25% crawl spaces, 43% elevated. Median water depth outside the building: 15 in.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 2 |
| 2018 | 0 |
| 2019 | 10 |
| 2020 | 14 |
| 2021 | 7 |
| 2022 | 2 |
| 2023 | 4 |
| 2024 | 0 |
| 2025 | 3 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 45.89 in |
| 12 months to August 2026 | 42.78 in (-3.11) |
| 2025 | 44.63 in (-1.26) |
| Wettest year since 1895 | 2003: 60.87 in |
| Driest year since 1895 | 2007: 28.90 in |
| Days with 1 inch or more, normal at BRISTOL TRI CITY AP (6 mi away) | 9.1 |
Homes
| Housing units | 76,324 |
| Median year built | 1977 |
| Built before 1980 | 55% |
| Built 2000 or later | 18% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $213,300 |
| Single-family detached | 70% |
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 |
|---|---|---|---|
| Bristol city, VA | 11 mi | 0% | 5% |
| Washington County, TN | 18 mi | 1% | 10% |
| Carter County, TN | 18 mi | 1% | 1% |
| Scott County, VA | 22 mi | 19% | 7% |
| Johnson County, TN | 25 mi | 0% | 1% |
| Washington County, VA | 25 mi | 1% | 7% |
| Unicoi County, TN | 29 mi | 0% | 1% |
| Russell County, VA | 31 mi | 13% | 5% |
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