Linn County, Iowa
A shallow water table limits basements on 57% of Linn County's mapped land, a higher share than 72% of US counties. Shrink-swell clay limits houses without basements on 9%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 199 flood losses here since 2016, 37% of them in buildings with basements. 53% of homes were built before 1980, against 50% nationally; the median home dates from 1978.
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 Linn County
| Expansive clay (limits slab homes) | 8.5% |
| High water table (limits basements) | 56.9% |
| Septic fields very limited | 89.8% |
| Clay swell (LEP, by area) | 3.4% |
| High-swell land (LEP 6%+) | 1.5% |
| Urban land, not rated | 1.8% |
| Mapped soil | 463,700 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Kenyon | 10% | n/a |
| Fayette | 8% | 0% |
| Clyde | 6% | n/a |
| Dinsdale | 6% | n/a |
| Dickinson | 5% | n/a |
| Sparta | 4% | n/a |
How we count · survey areas IA113 (2025-09-08)
What the numbers mean here
On 57% of Linn 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: 36.70 in, 0.87 in below the 1991-2020 average year of 37.57 in.
USDA rates 90% 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 17 of the last 52 weeks; the most was 100% of its area, in 7 weeks, most recently on the December 30, 2025 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
199 flood losses since 2016, $1.3 million paid. The worst year was 2016, with 188. Foundations of the buildings, where recorded: 37% basements, 55% slabs, 2% crawl spaces, 6% elevated. Median water depth outside the building: 12 in.
| Year | Flood losses |
|---|---|
| 2016 | 188 |
| 2017 | 0 |
| 2018 | 3 |
| 2019 | 2 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 3 |
| 2026 to date | 1 |
Rain
| Average year, 1991-2020 | 37.57 in |
| 12 months to August 2026 | 36.70 in (-0.87) |
| 2025 | 33.03 in (-4.54) |
| Wettest year since 1895 | 1993: 56.95 in |
| Driest year since 1895 | 1910: 19.02 in |
| Days with 1 inch or more, normal at CEDAR RAPIDS #1 (2 mi away) | 9.4 |
Homes
| Housing units | 103,104 |
| Median year built | 1978 |
| Built before 1980 | 53% |
| Built 2000 or later | 27% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $214,300 |
| Single-family detached | 67% |
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 |
|---|---|---|---|
| Benton County, IA | 24 mi | 33% | 73% |
| Jones County, IA | 25 mi | 12% | 38% |
| Johnson County, IA | 28 mi | 40% | 56% |
| Delaware County, IA | 30 mi | 4% | 53% |
| Buchanan County, IA | 30 mi | 2% | 78% |
| Cedar County, IA | 32 mi | 39% | 43% |
| Iowa County, IA | 36 mi | 57% | 69% |
| Black Hawk County, IA | 45 mi | 9% | 75% |
Sources: USDA SSURGO (September 8, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status