Will County, Illinois
A shallow water table limits basements on 85% of Will County's mapped land, a higher share than 92% of US counties. Shrink-swell clay limits houses without basements on 24%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 158 flood losses here since 2016, 46% of them in buildings with basements. 37% of homes were built before 1980, against 50% nationally; the median home dates from 1992.
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 Will County
| Expansive clay (limits slab homes) | 24.3% |
| High water table (limits basements) | 85.2% |
| Septic fields very limited | 95.6% |
| Clay swell (LEP, by area) | 4.6% |
| High-swell land (LEP 6%+) | 21.2% |
| Urban land, not rated | 1.1% |
| Mapped soil | 543,635 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Ashkum | 16% | n/a |
| Elliott | 16% | n/a |
| Ozaukee | 6% | over 99% |
| Beecher | 5% | n/a |
| Markham | 4% | n/a |
| Varna | 3% | n/a |
How we count · survey areas IL197 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 4.6% by land area here, and 21% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 24% of the mapped land.
On 85% of Will 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: 42.63 in, 3.41 in above the 1991-2020 average year of 39.22 in.
USDA rates 96% 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 12 of the last 52 weeks; the most was 79.4% 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
158 flood losses since 2016, $2.0 million paid. The worst year was 2019, with 40. Foundations of the buildings, where recorded: 46% basements, 29% slabs, 4% crawl spaces, 21% elevated. Median water depth outside the building: 12 in.
| Year | Flood losses |
|---|---|
| 2016 | 3 |
| 2017 | 20 |
| 2018 | 18 |
| 2019 | 40 |
| 2020 | 37 |
| 2021 | 8 |
| 2022 | 6 |
| 2023 | 2 |
| 2024 | 12 |
| 2025 | 5 |
| 2026 to date | 7 |
Rain
| Average year, 1991-2020 | 39.22 in |
| 12 months to August 2026 | 42.63 in (+3.41) |
| 2025 | 30.36 in (-8.86) |
| Wettest year since 1895 | 1902: 53.08 in |
| Driest year since 1895 | 1963: 23.83 in |
| Days with 1 inch or more, normal at JOLIET BRANDON RD DAM (8 mi away) | 8.3 |
Homes
| Housing units | 254,278 |
| Median year built | 1992 |
| Built before 1980 | 37% |
| Built 2000 or later | 33% |
| Owner-occupied | 83% |
| Median value, owner-occupied | $319,600 |
| Single-family detached | 74% |
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 |
|---|---|---|---|
| Kankakee County, IL | 22 mi | 19% | 80% |
| Grundy County, IL | 24 mi | 30% | 85% |
| Kendall County, IL | 25 mi | 26% | 85% |
| DuPage County, IL | 28 mi | 33% | 90% |
| Lake County, IN | 31 mi | 16% | 77% |
| Cook County, IL | 35 mi | 25% | 59% |
| Kane County, IL | 41 mi | 8% | 82% |
| Newton County, IN | 45 mi | 4% | 88% |
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