Scott County, Illinois
A shallow water table limits basements on 47% of Scott County's mapped land, a higher share than 64% of US counties. Shrink-swell clay limits houses without basements on 27%.
3.6% 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. 73% of homes were built before 1980, against 50% nationally; the median home dates from 1963.
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 Scott County
| Expansive clay (limits slab homes) | 27.1% |
| High water table (limits basements) | 47.0% |
| Septic fields very limited | 65.7% |
| Clay swell (LEP, by area) | 4.4% |
| High-swell land (LEP 6%+) | 21.2% |
| Mapped soil | 161,550 acres |
How we count · survey areas IL171 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 4.4% by land area here, and 21% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 27% of the mapped land.
Clay shrinks as it dries: 3.6% of the county is in drought on the latest map, and 27% of Scott County's mapped land has shrink-swell clay.
On 47% of Scott 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: 33.35 in, 5.80 in below the 1991-2020 average year of 39.15 in.
USDA rates 66% of the land very limited for septic absorption fields.
Drought
3.6% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 27 of the last 52 weeks; the most was 100% of its area, in 21 weeks, most recently on the March 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 89.1% |
| D1 moderate drought or worse | 3.6% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Scott County since 2016.
Rain
| Average year, 1991-2020 | 39.15 in |
| 12 months to August 2026 | 33.35 in (-5.80) |
| 2025 | 27.52 in (-11.63) |
| Wettest year since 1895 | 1993: 53.92 in |
| Driest year since 1895 | 1901: 23.45 in |
| Days with 1 inch or more, normal at WHITE HALL 1 E (15 mi away) | 10.3 |
Homes
| Housing units | 2,384 |
| Median year built | 1963 |
| Built before 1980 | 73% |
| Built 2000 or later | 12% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $96,400 |
| Single-family detached | 82% |
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 |
|---|---|---|---|
| Morgan County, IL | 16 mi | 43% | 54% |
| Greene County, IL | 20 mi | 20% | 51% |
| Pike County, IL | 22 mi | 9% | 56% |
| Cass County, IL | 26 mi | 13% | 45% |
| Brown County, IL | 27 mi | 29% | 38% |
| Calhoun County, IL | 34 mi | 4% | 25% |
| Schuyler County, IL | 37 mi | 31% | 46% |
| Jersey County, IL | 39 mi | 22% | 53% |
Sources: USDA SSURGO (August 31, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status