Greene County, Illinois
A shallow water table limits basements on 51% of Greene County's mapped land, a higher share than 67% of US counties. Shrink-swell clay limits houses without basements on 20%.
77.3% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 2 flood losses here since 2016. 76% of homes were built before 1980, against 50% nationally; the median home dates from 1957.
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 Greene County
| Expansive clay (limits slab homes) | 20.1% |
| High water table (limits basements) | 51.2% |
| Septic fields very limited | 63.4% |
| Clay swell (LEP, by area) | 4.3% |
| High-swell land (LEP 6%+) | 18.4% |
| Mapped soil | 349,810 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Fayette | 16% | 0% |
| Rozetta | 11% | n/a |
| Muscatune | 9% | n/a |
| Hickory | 8% | n/a |
| Keomah | 6% | n/a |
| Lawson | 5% | n/a |
How we count · survey areas IL061 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 4.3% by land area here, and 18% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 20% of the mapped land.
Clay shrinks as it dries: 77.3% of the county is in drought on the latest map, and 20% of Greene County's mapped land has shrink-swell clay.
On 51% of Greene 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: 30.89 in, 9.45 in below the 1991-2020 average year of 40.34 in.
USDA rates 63% of the land very limited for septic absorption fields.
Drought
77.3% 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 15 weeks, most recently on the March 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 77.3% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $17,291 paid. The worst year was 2024, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 2 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 40.34 in |
| 12 months to August 2026 | 30.89 in (-9.45) |
| 2025 | 29.04 in (-11.30) |
| Wettest year since 1895 | 2015: 57.00 in |
| Driest year since 1895 | 1901: 23.53 in |
| Days with 1 inch or more, normal at WHITE HALL 1 E (6 mi away) | 10.3 |
Homes
| Housing units | 5,785 |
| Median year built | 1957 |
| Built before 1980 | 76% |
| Built 2000 or later | 8% |
| Owner-occupied | 78% |
| Median value, owner-occupied | $95,200 |
| Single-family detached | 83% |
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 |
|---|---|---|---|
| Jersey County, IL | 19 mi | 22% | 53% |
| Calhoun County, IL | 20 mi | 4% | 25% |
| Scott County, IL | 20 mi | 27% | 47% |
| Macoupin County, IL | 25 mi | 62% | 78% |
| Morgan County, IL | 27 mi | 43% | 54% |
| Pike County, IL | 33 mi | 9% | 56% |
| Lincoln County, MO | 37 mi | 64% | 55% |
| Pike County, MO | 42 mi | 45% | 69% |
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