HomeSouth DakotaBennett County

Bennett County, South Dakota

USDA's soil survey flags shrink-swell clay on 10% of Bennett County's mapped land and a shallow water table under basements on 8%, both below the national shares of 15% and 29%. 52.7% of the county is in drought on the October 13, 2026 Drought Monitor map.

FEMA's flood data list no flood losses here since 2016. 63% of homes were built before 1980, against 50% nationally; the median home dates from 1973.

Data as of October 13, 2026 · sources

10%

expansive clay: shrink-swell limits slab homes

8%

high water table: limits basements

53%

in drought, October 13, 2026

63%

of homes built before 1980

Soil under Bennett County

Expansive clay (limits slab homes)9.9%
High water table (limits basements)8.5%
Septic fields very limited79.0%
Clay swell (LEP, by area)2.6%
High-swell land (LEP 6%+)9.4%
Mapped soil761,152 acres
Soil seriesShare hereSeries nationally: expansive clay
Valentine24%0%
Keith11%n/a
Canyon11%n/a
Oglala9%n/a
Rosebud6%n/a
Anselmo3%n/a
Jackson County: 45%Oglala Lakota County: 23%Todd County: 12%Cherry County: 0%Mellette County: 61%Sheridan County: 2%Jones County: 94%Haakon County: 89%Bennett County JacksonOglala LakotaToddCherryMelletteSheridanJonesHaakonBennett
Bennett 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 SD007 (2025-09-09)

What the numbers mean here

Rain over the 12 months to August 2026: 18.17 in, 2.92 in below the 1991-2020 average year of 21.09 in.

USDA rates 79% of the land very limited for septic absorption fields.

With shrink-swell clay on 10% and a shallow water table on 8% of the land, the soil survey points to neither problem across most of Bennett County; conditions still vary lot by lot.

Drought

52.7% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 36 of the last 52 weeks; the most was 100% of its area, in 26 weeks, most recently on the August 18, 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 worse52.7%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

FEMA's flood data list no flood losses in Bennett County since 2016.

Rain

Average year, 1991-202021.09 in
12 months to August 202618.17 in (-2.92)
202520.32 in (-0.77)
Wettest year since 18952019: 33.98 in
Driest year since 18951940: 10.59 in
Days with 1 inch or more, normal at MARTIN (3 mi away)3.6

Homes

Housing units1,151
Median year built1973
Built before 198063%
Built 2000 or later9%
Owner-occupied61%
Median value, owner-occupied$156,400
Single-family detached83%

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
Jackson County, SD 34 mi 45% 2%
Oglala Lakota County, SD 46 mi 23% 1%
Todd County, SD 49 mi 12% 9%
Cherry County, NE 53 mi under 1% 16%
Mellette County, SD 54 mi 61% 3%
Sheridan County, NE 58 mi 2% 11%
Jones County, SD 73 mi 94% 7%
Haakon County, SD 76 mi 89% 6%

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