HomeSouth DakotaMcCook County

McCook County, South Dakota

A shallow water table limits basements on 33% of McCook County's mapped land, a higher share than 51% of US counties. Shrink-swell clay limits houses without basements on 26%.

100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 18 flood losses here since 2016. 62% of homes were built before 1980, against 50% nationally; the median home dates from 1970.

Data as of October 13, 2026 · sources

26%

expansive clay: shrink-swell limits slab homes

33%

high water table: limits basements

100%

in drought, October 13, 2026

62%

of homes built before 1980

Soil under McCook County

Expansive clay (limits slab homes)25.7%
High water table (limits basements)32.7%
Septic fields very limited89.4%
Clay swell (LEP, by area)4.4%
High-swell land (LEP 6%+)26.1%
Mapped soil368,439 acres
Soil seriesShare hereSeries nationally: high water table
Clarno31%0%
Crossplain15%n/a
Bonilla8%n/a
Ethan7%n/a
Hand7%n/a
Tetonka5%n/a
Hanson County: 25%Miner County: 28%Lake County: 27%Turner County: 39%Minnehaha County: 32%Hutchinson County: 25%Davison County: 20%Moody County: 36%McCook County HansonMinerLakeTurnerMinnehahaHutchinsonDavisonMoodyMcCook
McCook 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 SD087 (2025-09-10)

What the numbers mean here

Clay swell averages a linear extensibility of 4.4% by land area here, and 26% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 26% of the mapped land.

Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 26% of McCook County's mapped land has shrink-swell clay.

On 33% of McCook 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: 17.96 in, 8.51 in below the 1991-2020 average year of 26.47 in.

USDA rates 89% of the land very limited for septic absorption fields.

Drought

100% 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 34 weeks, most recently on the October 13, 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 worse100%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

18 flood losses since 2016, $534,101 paid. The worst year was 2019, with 11.

YearFlood losses
20160
20170
20180
201911
20200
20210
20220
20230
20247
20250
2026 to date0

Rain

Average year, 1991-202026.47 in
12 months to August 202617.96 in (-8.51)
202524.78 in (-1.69)
Wettest year since 18952019: 40.22 in
Driest year since 18951976: 13.80 in
Days with 1 inch or more, normal at MARION (19 mi away)5.4

Homes

Housing units2,473
Median year built1970
Built before 198062%
Built 2000 or later20%
Owner-occupied80%
Median value, owner-occupied$230,100
Single-family detached86%

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
Hanson County, SD 22 mi 21% 25%
Miner County, SD 26 mi 41% 28%
Lake County, SD 27 mi 30% 27%
Turner County, SD 28 mi 20% 39%
Minnehaha County, SD 28 mi 17% 32%
Hutchinson County, SD 31 mi 21% 25%
Davison County, SD 40 mi 18% 20%
Moody County, SD 41 mi 10% 36%

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