Richland County, Illinois
A shallow water table limits basements on 93% of Richland County's mapped land, a higher share than 97% of US counties and the 10th highest of 102 Illinois counties. Shrink-swell clay limits houses without basements on 44%.
98.5% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list no flood losses here since 2016. 65% of homes were built before 1980, against 50% nationally; the median home dates from 1973.
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 Richland County
| Expansive clay (limits slab homes) | 44.0% |
| High water table (limits basements) | 92.7% |
| Septic fields very limited | 91.9% |
| Clay swell (LEP, by area) | 5.3% |
| High-swell land (LEP 6%+) | 58.7% |
| Mapped soil | 231,430 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Cisne | 19% | n/a |
| Bluford | 19% | 100% |
| Hoyleton | 12% | n/a |
| Wynoose | 9% | n/a |
| Belknap | 8% | n/a |
| Ava | 7% | n/a |
How we count · survey areas IL159 (2025-09-01)
What the numbers mean here
Clay swell averages a linear extensibility of 5.3% by land area here, and 59% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 44% of the mapped land.
Clay shrinks as it dries: 98.5% of the county is in drought on the latest map, and 44% of Richland County's mapped land has shrink-swell clay.
On 93% of Richland 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: 41.50 in, 5.10 in below the 1991-2020 average year of 46.60 in.
USDA rates 92% of the land very limited for septic absorption fields.
Drought
98.5% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 25 of the last 52 weeks; the most was 100% of its area, in 12 weeks, most recently on the March 3, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 98.5% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Richland County since 2016.
Rain
| Average year, 1991-2020 | 46.60 in |
| 12 months to August 2026 | 41.50 in (-5.10) |
| 2025 | 46.12 in (-0.48) |
| Wettest year since 1895 | 2011: 61.73 in |
| Driest year since 1895 | 1953: 26.78 in |
| Days with 1 inch or more, normal at OLNEY 2S (1 mi away) | 13.6 |
Homes
| Housing units | 7,363 |
| Median year built | 1973 |
| Built before 1980 | 65% |
| Built 2000 or later | 14% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $112,000 |
| Single-family detached | 77% |
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 |
|---|---|---|---|
| Lawrence County, IL | 19 mi | 23% | 78% |
| Edwards County, IL | 21 mi | 21% | 92% |
| Jasper County, IL | 21 mi | 51% | 89% |
| Clay County, IL | 21 mi | 44% | 91% |
| Wabash County, IL | 23 mi | 14% | 74% |
| Crawford County, IL | 27 mi | 43% | 81% |
| Wayne County, IL | 27 mi | 26% | 94% |
| Effingham County, IL | 36 mi | 43% | 87% |
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