Humboldt County, Iowa
A shallow water table limits basements on 90% of Humboldt County's mapped land, a higher share than 96% of US counties and the 5th highest of 99 Iowa counties. Shrink-swell clay limits houses without basements on 10%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 76% of homes were built before 1980, against 50% nationally; the median home dates from 1961.
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 Humboldt County
| Expansive clay (limits slab homes) | 9.8% |
| High water table (limits basements) | 90.1% |
| Septic fields very limited | 94.2% |
| Clay swell (LEP, by area) | 4.1% |
| High-swell land (LEP 6%+) | 9.4% |
| Mapped soil | 279,400 acres |
How we count · survey areas IA091 (2025-09-08)
What the numbers mean here
On 90% of Humboldt 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: 28.13 in, 5.28 in below the 1991-2020 average year of 33.41 in.
USDA rates 94% 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 15 of the last 52 weeks; the most was 100% of its area, on the August 4, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 13.1% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $0 paid. The worst year was 2024, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 33.41 in |
| 12 months to August 2026 | 28.13 in (-5.28) |
| 2025 | 34.11 in (+0.70) |
| Wettest year since 1895 | 1993: 45.79 in |
| Driest year since 1895 | 2022: 19.40 in |
| Days with 1 inch or more, normal at FT DODGE 5NNW (14 mi away) | 8.3 |
Homes
| Housing units | 4,603 |
| Median year built | 1961 |
| Built before 1980 | 76% |
| Built 2000 or later | 14% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $155,800 |
| Single-family detached | 85% |
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 |
|---|---|---|---|
| Wright County, IA | 24 mi | 27% | 89% |
| Webster County, IA | 24 mi | 27% | 88% |
| Pocahontas County, IA | 24 mi | 13% | 93% |
| Kossuth County, IA | 30 mi | 18% | 90% |
| Hancock County, IA | 31 mi | 16% | 87% |
| Palo Alto County, IA | 31 mi | 10% | 85% |
| Calhoun County, IA | 35 mi | 13% | 91% |
| Hamilton County, IA | 37 mi | 32% | 91% |
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