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Alleghany County, North Carolina

USDA's soil survey flags shrink-swell clay on 0% of Alleghany County's mapped land and a shallow water table under basements on 5%, both below the national shares of 15% and 29%. None of the county is in drought on the October 13, 2026 Drought Monitor map, after 2.9% a week earlier.

FEMA's flood data list 7 flood losses here since 2016. 51% of homes were built before 1980, against 50% nationally; the median home dates from 1980.

Data as of October 13, 2026 · sources

0%

expansive clay: shrink-swell limits slab homes

5%

high water table: limits basements

0%

in drought, October 13, 2026

51%

of homes built before 1980

Soil under Alleghany County

Expansive clay (limits slab homes)0.0%
High water table (limits basements)5.3%
Septic fields very limited94.7%
Clay swell (LEP, by area)1.6%
High-swell land (LEP 6%+)0.0%
Mapped soil150,093 acres
Soil seriesShare hereSeries nationally: expansive clay
Watauga24%n/a
Chester24%n/a
Chandler8%n/a
Ashe7%n/a
Porters6%n/a
Fannin5%n/a
Grayson County: 1%Galax city: 1%Wilkes County: 0%Ashe County: 0%Surry County: 0%Carroll County: 1%Wythe County: 6%Smyth County: 11%Alleghany County GraysonGalax cityWilkesAsheSurryCarrollWytheSmythAlleghany
Alleghany 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 NC005 (2025-09-02)

What the numbers mean here

Rain over the 12 months to August 2026: 38.79 in, 15.76 in below the 1991-2020 average year of 54.55 in.

USDA rates 95% of the land very limited for septic absorption fields.

With shrink-swell clay on 0% and a shallow water table on 5% of the land, the soil survey points to neither problem across most of Alleghany County; conditions still vary lot by lot.

Drought

0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 45 of the last 52 weeks; the most was 100% of its area, in 32 weeks, most recently on the September 22, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse8.7%
D1 moderate drought or worse0%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

7 flood losses since 2016, $385,497 paid. The worst year was 2024, with 4.

YearFlood losses
20160
20170
20183
20190
20200
20210
20220
20230
20244
20250
2026 to date0

Rain

Average year, 1991-202054.55 in
12 months to August 202638.79 in (-15.76)
202542.59 in (-11.96)
Wettest year since 18952018: 83.53 in
Driest year since 18951930: 31.41 in
Days with 1 inch or more, normal at TRANSOU (11 mi away)16.1

Homes

Housing units7,804
Median year built1980
Built before 198051%
Built 2000 or later21%
Owner-occupied74%
Median value, owner-occupied$214,800
Single-family detached77%

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
Grayson County, VA 12 mi 1% 6%
Galax city, VA 17 mi 1% 9%
Wilkes County, NC 19 mi 0% 6%
Ashe County, NC 21 mi 0% 4%
Surry County, NC 25 mi under 1% 4%
Carroll County, VA 28 mi 1% 5%
Wythe County, VA 29 mi 6% 8%
Smyth County, VA 33 mi 11% 5%

Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status