HomeNorth DakotaMercer County

Mercer County, North Dakota

Shrink-swell clay limits houses without basements on 15% of Mercer County's mapped land, a higher share than 64% of US counties. A shallow water table limits basements on 4%.

100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 3 flood losses here since 2016. 49% of homes were built before 1980, against 50% nationally; the median home dates from 1981.

Data as of October 13, 2026 · sources

15%

expansive clay: shrink-swell limits slab homes

4%

high water table: limits basements

100%

in drought, October 13, 2026

49%

of homes built before 1980

Soil under Mercer County

Expansive clay (limits slab homes)15.2%
High water table (limits basements)3.9%
Septic fields very limited76.8%
Clay swell (LEP, by area)3.9%
High-swell land (LEP 6%+)16.5%
Mapped soil712,200 acres
Soil seriesShare hereSeries nationally: expansive clay
Williams12%0%
Werner6%n/a
Bowbells5%n/a
Amor5%n/a
Zahl4%n/a
Arnegard3%n/a
Oliver County: 13%McLean County: 9%Dunn County: 22%Morton County: 32%Stark County: 37%Ward County: 12%Grant County: 23%Hettinger County: 43%Mercer County OliverMcLeanDunnMortonStarkWardGrantHettingerMercer
Mercer 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 ND057 (2026-05-04)

What the numbers mean here

Clay swell averages a linear extensibility of 3.9% by land area here, and 16% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 15% of the mapped land.

Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 15% of Mercer County's mapped land has shrink-swell clay.

Rain over the 12 months to August 2026: 14.63 in, 2.68 in below the 1991-2020 average year of 17.31 in.

USDA rates 77% 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 12 of the last 52 weeks; the most was 100% of its area, in 11 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 worse48%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

3 flood losses since 2016, $17,679 paid. The worst year was 2023, with 3.

YearFlood losses
20160
20170
20180
20190
20200
20210
20220
20233
20240
20250
2026 to date0

Rain

Average year, 1991-202017.31 in
12 months to August 202614.63 in (-2.68)
202519.58 in (+2.27)
Wettest year since 18952013: 26.13 in
Driest year since 18951936: 6.84 in
Days with 1 inch or more, normal at HEBRON (29 mi away)3.4

Homes

Housing units4,667
Median year built1981
Built before 198049%
Built 2000 or later23%
Owner-occupied81%
Median value, owner-occupied$198,500
Single-family detached73%

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
Oliver County, ND 26 mi 13% 5%
McLean County, ND 31 mi 9% 13%
Dunn County, ND 37 mi 22% 5%
Morton County, ND 48 mi 32% 5%
Stark County, ND 52 mi 37% 4%
Ward County, ND 64 mi 12% 44%
Grant County, ND 66 mi 23% 5%
Hettinger County, ND 67 mi 43% 7%

Sources: USDA SSURGO (May 4, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status