Anderson County, Tennessee
USDA's soil survey flags shrink-swell clay on 2% of Anderson County's mapped land and a shallow water table under basements on 7%, both below the national shares of 15% and 29%. 4.5% of the county is in drought on the October 13, 2026 Drought Monitor map, down from 14.1% a week earlier.
FEMA's flood data list 13 flood losses here since 2016. 54% 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 Anderson County
| Expansive clay (limits slab homes) | 2.1% |
| High water table (limits basements) | 6.7% |
| Septic fields very limited | 87.0% |
| Clay swell (LEP, by area) | 2.3% |
| High-swell land (LEP 6%+) | 2.4% |
| Mapped soil | 220,600 acres |
How we count · survey areas TN001 (2025-08-27)
What the numbers mean here
Rain over the 12 months to August 2026: 54.03 in, 3.44 in below the 1991-2020 average year of 57.47 in.
USDA rates 87% of the land very limited for septic absorption fields.
With shrink-swell clay on 2% and a shallow water table on 7% of the land, the soil survey points to neither problem across most of Anderson County; conditions still vary lot by lot.
Drought
4.5% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 32 of the last 52 weeks; the most was 100% of its area, in 7 weeks, most recently on the May 26, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 97.4% |
| D1 moderate drought or worse | 4.5% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
13 flood losses since 2016, $69,523 paid. The worst year was 2020, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 1 |
| 2018 | 1 |
| 2019 | 1 |
| 2020 | 3 |
| 2021 | 1 |
| 2022 | 1 |
| 2023 | 1 |
| 2024 | 2 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 57.47 in |
| 12 months to August 2026 | 54.03 in (-3.44) |
| 2025 | 53.39 in (-4.08) |
| Wettest year since 1895 | 2019: 71.95 in |
| Driest year since 1895 | 2007: 37.73 in |
| Days with 1 inch or more, normal at OAK RIDGE ATDD (8 mi away) | 17.2 |
Homes
| Housing units | 35,880 |
| Median year built | 1977 |
| Built before 1980 | 54% |
| Built 2000 or later | 19% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $239,400 |
| Single-family detached | 72% |
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 |
|---|---|---|---|
| Knox County, TN | 17 mi | 0% | 8% |
| Campbell County, TN | 20 mi | 0% | 2% |
| Union County, TN | 23 mi | under 1% | 5% |
| Morgan County, TN | 25 mi | 0% | 2% |
| Roane County, TN | 26 mi | 2% | 7% |
| Loudon County, TN | 27 mi | under 1% | 4% |
| Scott County, TN | 28 mi | 0% | 2% |
| Blount County, TN | 33 mi | under 1% | 5% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status