Kankakee County, Illinois
A shallow water table limits basements on 80% of Kankakee County's mapped land, a higher share than 88% of US counties. Shrink-swell clay limits houses without basements on 19%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 91 flood losses here since 2016, 55% of them in buildings with basements. 65% of homes were built before 1980, against 50% nationally; the median home dates from 1972.
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 Kankakee County
| Expansive clay (limits slab homes) | 19.3% |
| High water table (limits basements) | 79.8% |
| Septic fields very limited | 96.8% |
| Clay swell (LEP, by area) | 3.8% |
| High-swell land (LEP 6%+) | 10.1% |
| Mapped soil | 435,925 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Reddick | 10% | n/a |
| Andres | 9% | n/a |
| Gilford | 7% | n/a |
| Elliott | 6% | n/a |
| Ashkum | 5% | n/a |
| Ridgeville | 4% | n/a |
How we count · survey areas IL091 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 3.8% by land area here, and 10% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 19% of the mapped land.
On 80% of Kankakee 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: 40.54 in, 1.25 in above the 1991-2020 average year of 39.29 in.
USDA rates 97% 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 21 of the last 52 weeks; the most was 49.1% of its area, in 2 weeks, most recently on the June 9, 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
91 flood losses since 2016, $4.2 million paid. The worst year was 2018, with 84. Foundations of the buildings, where recorded: 55% basements, 3% slabs, 29% crawl spaces, 13% elevated. Median water depth outside the building: 18 in.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 0 |
| 2018 | 84 |
| 2019 | 1 |
| 2020 | 2 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 39.29 in |
| 12 months to August 2026 | 40.54 in (+1.25) |
| 2025 | 32.33 in (-6.96) |
| Wettest year since 1895 | 1993: 51.48 in |
| Driest year since 1895 | 1963: 22.72 in |
| Days with 1 inch or more, normal at BOURBONNAIS 3NW (5 mi away) | 8.5 |
Homes
| Housing units | 45,415 |
| Median year built | 1972 |
| Built before 1980 | 65% |
| Built 2000 or later | 17% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $192,600 |
| Single-family detached | 71% |
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 |
|---|---|---|---|
| Will County, IL | 22 mi | 24% | 85% |
| Newton County, IN | 27 mi | 4% | 88% |
| Iroquois County, IL | 27 mi | 44% | 93% |
| Grundy County, IL | 30 mi | 30% | 85% |
| Lake County, IN | 34 mi | 16% | 77% |
| Jasper County, IN | 40 mi | 5% | 86% |
| Livingston County, IL | 40 mi | 53% | 96% |
| Ford County, IL | 42 mi | 55% | 98% |
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