Davison County, South Dakota

A shallow water table limits basements on 20% of Davison County's mapped land. Shrink-swell clay limits houses without basements on 18%.

35.7% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 17 flood losses here since 2016. 64% 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

20%

high water table: limits basements

36%

in drought, October 13, 2026

64%

of homes built before 1980

Soil under Davison County

Expansive clay (limits slab homes)	18.1%
High water table (limits basements)	20.0%
Septic fields very limited	95.9%
Clay swell (LEP, by area)	4.3%
High-swell land (LEP 6%+)	20.3%
Mapped soil	259,804 acres

Soil series	Share here	Series nationally: high water table
Houdek	19%	n/a
Clarno	14%	0%
Prosper	10%	n/a
Tetonka	8%	n/a
Bonilla	7%	n/a
Stickney	7%	n/a

Davison 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 SD035 (2025-09-10)

What the numbers mean here

Clay swell averages a linear extensibility of 4.3% by land area here, and 20% 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.

Clay shrinks as it dries: 35.7% of the county is in drought on the latest map, and 18% of Davison County's mapped land has shrink-swell clay.

On 20% of Davison 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: 16.78 in, 8.33 in below the 1991-2020 average year of 25.11 in.

USDA rates 96% of the land very limited for septic absorption fields.

Drought

35.7% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 38 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, 2026	Share of county
D0 abnormally dry or worse	100%
D1 moderate drought or worse	35.7%
D2 severe or worse	0%
D3 extreme or worse	0%
D4 exceptional	0%

Flood losses since 2016

17 flood losses since 2016, $1.9 million paid. The worst year was 2024, with 10.

Year	Flood losses
2016	0
2017	0
2018	1
2019	5
2020	1
2021	0
2022	0
2023	0
2024	10
2025	0
2026 to date	0

Rain

Average year, 1991-2020	25.11 in
12 months to August 2026	16.78 in (-8.33)
2025	23.13 in (-1.98)
Wettest year since 1895	2019: 42.89 in
Driest year since 1895	1974: 12.81 in
Days with 1 inch or more, normal at ALEXANDRIA (18 mi away)	6.4

Homes

Housing units	9,579
Median year built	1972
Built before 1980	64%
Built 2000 or later	21%
Owner-occupied	62%
Median value, owner-occupied	$205,800
Single-family detached	64%

What repairs cost

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

Work	Range	Source
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

Place	Distance	Expansive clay	High water table
Hanson County, SD	18 mi	21%	25%
Aurora County, SD	21 mi	42%	19%
Douglas County, SD	22 mi	33%	21%
Sanborn County, SD	24 mi	28%	40%
Hutchinson County, SD	31 mi	21%	25%
Jerauld County, SD	35 mi	34%	22%
Miner County, SD	36 mi	41%	28%
Charles Mix County, SD	40 mi	29%	13%

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