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Allamakee County, Iowa

Shrink-swell clay limits houses without basements on 18% of Allamakee County's mapped land, a higher share than 68% of US counties. A shallow water table limits basements on 11%.

None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 7 flood losses here since 2016. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1972.

Data as of October 13, 2026 · sources

18%

expansive clay: shrink-swell limits slab homes

11%

high water table: limits basements

0%

in drought, October 13, 2026

58%

of homes built before 1980

Soil under Allamakee County

Expansive clay (limits slab homes)18.3%
High water table (limits basements)10.9%
Septic fields very limited93.3%
Clay swell (LEP, by area)4.8%
High-swell land (LEP 6%+)29.9%
Mapped soil422,200 acres
Soil seriesShare hereSeries nationally: expansive clay
Fayette22%under 1%
Downs12%n/a
Lacrescent12%n/a
Village9%n/a
Paintcreek7%n/a
Nordness5%n/a
Crawford County: 5%Winneshiek County: 6%Houston County: 5%Clayton County: 1%Vernon County: 8%Fayette County: 1%Grant County: 23%Fillmore County: 8%Allamakee County CrawfordWinneshiekHoustonClaytonVernonFayetteGrantFillmoreAllamakee
Allamakee County (heavy outline) and nearby counties, shaded by expansive clay share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas IA005 (2025-09-05)

What the numbers mean here

Clay swell averages a linear extensibility of 4.8% by land area here, and 30% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 18% of the mapped land.

Rain over the 12 months to August 2026: 32.32 in, 5.98 in below the 1991-2020 average year of 38.30 in.

USDA rates 93% 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 1 of the last 52 weeks; the most was 2.7% of its area, on the June 23, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse0%
D1 moderate drought or worse0%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

7 flood losses since 2016, $54,317 paid. The worst year was 2016, with 3.

YearFlood losses
20163
20170
20180
20192
20200
20210
20220
20231
20241
20250
2026 to date0

Rain

Average year, 1991-202038.30 in
12 months to August 202632.32 in (-5.98)
202528.33 in (-9.97)
Wettest year since 18952018: 55.17 in
Driest year since 18951958: 19.65 in
Days with 1 inch or more, normal at LYNXVILLE DAM 9 (15 mi away)8.6

Homes

Housing units7,761
Median year built1972
Built before 198058%
Built 2000 or later20%
Owner-occupied80%
Median value, owner-occupied$172,300
Single-family detached75%

What repairs cost

Published ranges from cost guides, not quotes. More sources, and where they disagree.

WorkRangeSource
Foundation repair, US $2,200 to $8,200 Fixr, January 27, 2026
Pier-and-beam repair, US $2,000 to $15,000 Fixr, January 27, 2026
Foundation inspection, US $300 to $600 Fixr, January 31, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Crawford County, WI 23 mi 5% 9%
Winneshiek County, IA 24 mi 6% 22%
Houston County, MN 28 mi 5% 16%
Clayton County, IA 30 mi 1% 14%
Vernon County, WI 36 mi 8% 8%
Fayette County, IA 37 mi 1% 59%
Grant County, WI 45 mi 23% 11%
Fillmore County, MN 45 mi 8% 21%

Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status