Douglas County, Illinois
A shallow water table limits basements on 96% of Douglas County's mapped land, a higher share than 99% of US counties and the 4th highest of 102 Illinois counties. Shrink-swell clay limits houses without basements on 72%.
None 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. 68% of homes were built before 1980, against 50% nationally; the median home dates from 1967.
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 Douglas County
| Expansive clay (limits slab homes) | 71.6% |
| High water table (limits basements) | 96.1% |
| Septic fields very limited | 98.6% |
| Clay swell (LEP, by area) | 5.8% |
| High-swell land (LEP 6%+) | 49.6% |
| Mapped soil | 266,970 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Drummer | 27% | over 99% |
| Milford | 22% | n/a |
| Flanagan | 19% | n/a |
| Elburn | 4% | n/a |
| Rutland | 3% | n/a |
| Sawmill | 2% | n/a |
How we count · survey areas IL041 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 5.8% by land area here, and 50% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 72% of the mapped land.
On 96% of Douglas 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: 42.75 in, 2.88 in above the 1991-2020 average year of 39.87 in.
USDA rates 99% of the land very limited for septic absorption fields.
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 24 of the last 52 weeks; the most was 100% of its area, in 22 weeks, most recently on the March 17, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
2 flood losses since 2016, $1,590 paid. The worst year was 2017, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 39.87 in |
| 12 months to August 2026 | 42.75 in (+2.88) |
| 2025 | 28.47 in (-11.40) |
| Wettest year since 1895 | 2009: 53.34 in |
| Driest year since 1895 | 1914: 24.75 in |
| Days with 1 inch or more, normal at TUSCOLA (4 mi away) | 10.1 |
Homes
| Housing units | 8,507 |
| Median year built | 1967 |
| Built before 1980 | 68% |
| Built 2000 or later | 14% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $150,400 |
| Single-family detached | 86% |
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 |
|---|---|---|---|
| Coles County, IL | 17 mi | 19% | 85% |
| Moultrie County, IL | 23 mi | 68% | 89% |
| Piatt County, IL | 26 mi | 57% | 94% |
| Champaign County, IL | 26 mi | 26% | 94% |
| Edgar County, IL | 26 mi | 16% | 83% |
| Cumberland County, IL | 34 mi | 39% | 84% |
| Clark County, IL | 38 mi | 29% | 77% |
| Vermilion County, IL | 39 mi | 34% | 90% |
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