HomeIowaClayton County

Clayton County, Iowa

USDA's soil survey flags shrink-swell clay on 1% of Clayton County's mapped land and a shallow water table under basements on 14%, both below the national shares of 15% and 29%. None of the county is in drought on the October 13, 2026 Drought Monitor map.

FEMA's flood data list 33 flood losses here since 2016, 48% of them in buildings with basements. 68% of homes were built before 1980, against 50% nationally; the median home dates from 1960.

Data as of October 13, 2026 · sources

1%

expansive clay: shrink-swell limits slab homes

14%

high water table: limits basements

0%

in drought, October 13, 2026

68%

of homes built before 1980

Soil under Clayton County

Expansive clay (limits slab homes)1.2%
High water table (limits basements)13.7%
Septic fields very limited94.3%
Clay swell (LEP, by area)4.6%
High-swell land (LEP 6%+)22.8%
Mapped soil509,000 acres
Soil seriesShare hereSeries nationally: expansive clay
Fayette35%under 1%
Downs11%n/a
Nordness9%n/a
Dubuque8%n/a
Exette3%n/a
Dorchester3%n/a
Delaware County: 4%Fayette County: 1%Allamakee County: 18%Grant County: 23%Crawford County: 5%Dubuque County: 9%Buchanan County: 2%Winneshiek County: 6%Clayton County DelawareFayetteAllamakeeGrantCrawfordDubuqueBuchananWinneshiekClayton
Clayton 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 IA043 (2025-09-08)

What the numbers mean here

Rain over the 12 months to August 2026: 36.84 in, 1.49 in below the 1991-2020 average year of 38.33 in.

USDA rates 94% of the land very limited for septic absorption fields.

With shrink-swell clay on 1% and a shallow water table on 14% of the land, the soil survey points to neither problem across most of Clayton County; conditions still vary lot by lot.

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 20.4% of its area, in 8 weeks, most recently on the January 6, 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

33 flood losses since 2016, $529,285 paid. The worst year was 2016, with 12. Foundations of the buildings, where recorded: 48% basements, 30% slabs, 4% crawl spaces, 17% elevated.

YearFlood losses
201612
20173
20182
20196
20200
20212
20220
20236
20242
20250
2026 to date0

Rain

Average year, 1991-202038.33 in
12 months to August 202636.84 in (-1.49)
202534.45 in (-3.88)
Wettest year since 18952018: 53.04 in
Driest year since 18951910: 21.46 in
Days with 1 inch or more, normal at ELKADER 6 SSW (8 mi away)8.4

Homes

Housing units8,796
Median year built1960
Built before 198068%
Built 2000 or later18%
Owner-occupied78%
Median value, owner-occupied$168,500
Single-family detached81%

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
Delaware County, IA 26 mi 4% 53%
Fayette County, IA 26 mi 1% 59%
Allamakee County, IA 30 mi 18% 11%
Grant County, WI 32 mi 23% 11%
Crawford County, WI 34 mi 5% 9%
Dubuque County, IA 34 mi 9% 25%
Buchanan County, IA 37 mi 2% 78%
Winneshiek County, IA 41 mi 6% 22%

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