Champaign County, Illinois
A shallow water table limits basements on 94% of Champaign County's mapped land, a higher share than 98% of US counties and the 7th highest of 102 Illinois counties. Shrink-swell clay limits houses without basements on 26%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 13 flood losses here since 2016. 48% of homes were built before 1980, against 50% nationally; the median home dates from 1981.
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 Champaign County
| Expansive clay (limits slab homes) | 26.4% |
| High water table (limits basements) | 93.9% |
| Septic fields very limited | 98.7% |
| Clay swell (LEP, by area) | 5.0% |
| High-swell land (LEP 6%+) | 23.2% |
| Mapped soil | 638,860 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Drummer | 38% | over 99% |
| Flanagan | 15% | n/a |
| Ashkum | 5% | n/a |
| Elliott | 5% | n/a |
| Dana | 3% | n/a |
| Raub | 3% | n/a |
How we count · survey areas IL019 (2025-09-01)
What the numbers mean here
Clay swell averages a linear extensibility of 5.0% by land area here, and 23% 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.
On 94% of Champaign 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: 40.34 in, 0.92 in above the 1991-2020 average year of 39.42 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 26 of the last 52 weeks; the most was 100% of its area, in 24 weeks, most recently on the March 31, 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
13 flood losses since 2016, $197,357 paid. The worst year was 2018, with 5.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 0 |
| 2018 | 5 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 2 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 2 |
| 2026 to date | 3 |
Rain
| Average year, 1991-2020 | 39.42 in |
| 12 months to August 2026 | 40.34 in (+0.92) |
| 2025 | 24.20 in (-15.22) |
| Wettest year since 1895 | 1993: 53.69 in |
| Driest year since 1895 | 2025: 24.20 in |
| Days with 1 inch or more, normal at CHAMPAIGN 3S (4 mi away) | 9.8 |
Homes
| Housing units | 95,115 |
| Median year built | 1981 |
| Built before 1980 | 48% |
| Built 2000 or later | 28% |
| Owner-occupied | 54% |
| Median value, owner-occupied | $211,500 |
| 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 |
|---|---|---|---|
| Piatt County, IL | 23 mi | 57% | 94% |
| Vermilion County, IL | 25 mi | 34% | 90% |
| Douglas County, IL | 26 mi | 72% | 96% |
| Ford County, IL | 32 mi | 55% | 98% |
| De Witt County, IL | 37 mi | 69% | 87% |
| Edgar County, IL | 40 mi | 16% | 83% |
| Moultrie County, IL | 41 mi | 68% | 89% |
| McLean County, IL | 42 mi | 54% | 85% |
Sources: USDA SSURGO (September 1, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status