Jackson County, Illinois
A shallow water table limits basements on 62% of Jackson County's mapped land, a higher share than 76% of US counties. Shrink-swell clay limits houses without basements on 26%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map, up from 0% a week earlier. FEMA's flood data list 10 flood losses here since 2016. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1976.
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 Jackson County
| Expansive clay (limits slab homes) | 25.9% |
| High water table (limits basements) | 62.5% |
| Septic fields very limited | 84.7% |
| Clay swell (LEP, by area) | 5.6% |
| High-swell land (LEP 6%+) | 29.3% |
| Mapped soil | 385,395 acres |
How we count · survey areas IL077 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 5.6% by land area here, and 29% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 26% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 26% of Jackson County's mapped land has shrink-swell clay.
On 62% of Jackson 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: 35.67 in, 10.82 in below the 1991-2020 average year of 46.49 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 28 of the last 52 weeks; the most was 100% of its area, in 11 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
10 flood losses since 2016, $1.0 million paid. The worst year was 2023, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 2 |
| 2018 | 1 |
| 2019 | 1 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 2 |
| 2024 | 1 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 46.49 in |
| 12 months to August 2026 | 35.67 in (-10.82) |
| 2025 | 40.34 in (-6.15) |
| Wettest year since 1895 | 1945: 68.74 in |
| Driest year since 1895 | 1901: 26.64 in |
| Days with 1 inch or more, normal at CARBONDALE SEWAGE PLT (12 mi away) | 13 |
Homes
| Housing units | 27,727 |
| Median year built | 1976 |
| Built before 1980 | 58% |
| Built 2000 or later | 18% |
| Owner-occupied | 50% |
| Median value, owner-occupied | $137,300 |
| Single-family detached | 52% |
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 |
|---|---|---|---|
| Perry County, IL | 21 mi | 24% | 75% |
| Union County, IL | 22 mi | 10% | 49% |
| Perry County, MO | 24 mi | 19% | 32% |
| Williamson County, IL | 25 mi | 16% | 74% |
| Franklin County, IL | 29 mi | 31% | 88% |
| Randolph County, IL | 30 mi | 24% | 64% |
| Cape Girardeau County, MO | 32 mi | 3% | 24% |
| Johnson County, IL | 35 mi | 2% | 78% |
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