HomeSouth DakotaHanson County

Hanson County, South Dakota

A shallow water table limits basements on 25% of Hanson County's mapped land. Shrink-swell clay limits houses without basements on 21%.

99.6% 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. 71% of homes were built before 1980, against 50% nationally; the median home dates from 1956.

Data as of October 13, 2026 · sources

21%

expansive clay: shrink-swell limits slab homes

25%

high water table: limits basements

100%

in drought, October 13, 2026

71%

of homes built before 1980

Soil under Hanson County

Expansive clay (limits slab homes)21.4%
High water table (limits basements)24.5%
Septic fields very limited90.1%
Clay swell (LEP, by area)4.4%
High-swell land (LEP 6%+)22.3%
Mapped soil800,417 acres
Soil seriesShare hereSeries nationally: high water table
Clarno30%0%
Bonilla11%n/a
Tetonka10%n/a
Hand7%n/a
Prosper6%n/a
Ethan5%n/a
Davison County: 20%McCook County: 33%Hutchinson County: 25%Miner County: 28%Sanborn County: 40%Douglas County: 21%Aurora County: 19%Lake County: 27%Hanson County DavisonMcCookHutchinsonMinerSanbornDouglasAuroraLakeHanson
Hanson County (heavy outline) and nearby counties, shaded by high water table share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas SD602 (2025-09-10)

What the numbers mean here

Clay swell averages a linear extensibility of 4.4% by land area here, and 22% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 21% of the mapped land.

Clay shrinks as it dries: 99.6% of the county is in drought on the latest map, and 21% of Hanson County's mapped land has shrink-swell clay.

On 25% of Hanson 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: 16.12 in, 9.31 in below the 1991-2020 average year of 25.43 in.

USDA rates 90% of the land very limited for septic absorption fields.

Drought

99.6% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 30 weeks, most recently on the September 15, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse100%
D1 moderate drought or worse99.6%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

7 flood losses since 2016, $136,449 paid. The worst year was 2019, with 7.

YearFlood losses
20160
20170
20180
20197
20200
20210
20220
20230
20240
20250
2026 to date0

Rain

Average year, 1991-202025.43 in
12 months to August 202616.12 in (-9.31)
202523.28 in (-2.15)
Wettest year since 18952019: 41.68 in
Driest year since 18951974: 12.63 in
Days with 1 inch or more, normal at ALEXANDRIA (2 mi away)6.4

Homes

Housing units1,291
Median year built1956
Built before 198071%
Built 2000 or later18%
Owner-occupied89%
Median value, owner-occupied$191,200
Single-family detached93%

What repairs cost

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

WorkRangeSource
Basement waterproofing, US $3,000 to $10,000 Fixr, February 6, 2026
Sump pump installation, US $800 to $2,000 Fixr, January 31, 2025
Crawl space encapsulation, US $2,000 to $8,000 Fixr, August 29, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Davison County, SD 18 mi 18% 20%
McCook County, SD 22 mi 26% 33%
Hutchinson County, SD 24 mi 21% 25%
Miner County, SD 25 mi 41% 28%
Sanborn County, SD 28 mi 28% 40%
Douglas County, SD 34 mi 33% 21%
Aurora County, SD 39 mi 42% 19%
Lake County, SD 41 mi 30% 27%

Sources: USDA SSURGO (September 10, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status