Black Hawk County, Iowa
A shallow water table limits basements on 75% of Black Hawk County's mapped land, a higher share than 85% 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 223 flood losses here since 2016, 54% of them in buildings with basements. 70% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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 Black Hawk County
| Expansive clay (limits slab homes) | 8.8% |
| High water table (limits basements) | 75.3% |
| Septic fields very limited | 91.4% |
| Clay swell (LEP, by area) | 3.4% |
| High-swell land (LEP 6%+) | 0.3% |
| Urban land, not rated | 3.8% |
| Mapped soil | 366,600 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Kenyon | 11% | n/a |
| Clyde | 8% | n/a |
| Marquis | 6% | n/a |
| Readlyn | 6% | n/a |
| Floyd | 5% | n/a |
| Dinsdale | 5% | n/a |
How we count · survey areas IA013 (2025-09-08)
What the numbers mean here
On 75% of Black Hawk 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: 36.12 in, 0.93 in below the 1991-2020 average year of 37.05 in.
USDA rates 91% 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 8 of the last 52 weeks; the most was 45.3% of its area, in 4 weeks, most recently on the December 9, 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
223 flood losses since 2016, $5.3 million paid. The worst year was 2016, with 181. Foundations of the buildings, where recorded: 54% basements, 14% slabs, 5% crawl spaces, 26% elevated. Median water depth outside the building: 23 in.
| Year | Flood losses |
|---|---|
| 2016 | 181 |
| 2017 | 0 |
| 2018 | 17 |
| 2019 | 16 |
| 2020 | 9 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 37.05 in |
| 12 months to August 2026 | 36.12 in (-0.93) |
| 2025 | 35.27 in (-1.78) |
| Wettest year since 1895 | 2018: 55.24 in |
| Driest year since 1895 | 1910: 19.08 in |
| Days with 1 inch or more, normal at WATERLOO MUNI AP (8 mi away) | 8.6 |
Homes
| Housing units | 58,991 |
| Median year built | 1966 |
| Built before 1980 | 70% |
| Built 2000 or later | 17% |
| Owner-occupied | 66% |
| Median value, owner-occupied | $188,900 |
| Single-family detached | 70% |
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 |
|---|---|---|---|
| Bremer County, IA | 21 mi | 4% | 78% |
| Buchanan County, IA | 23 mi | 2% | 78% |
| Grundy County, IA | 26 mi | 59% | 67% |
| Benton County, IA | 29 mi | 33% | 73% |
| Tama County, IA | 30 mi | 42% | 49% |
| Butler County, IA | 30 mi | 9% | 73% |
| Fayette County, IA | 35 mi | 1% | 59% |
| Chickasaw County, IA | 40 mi | 3% | 82% |
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