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Arlington County, Virginia

USDA's soil survey flags shrink-swell clay on 0% of Arlington County's mapped land and a shallow water table under basements on 3%, both below the national shares of 15% and 29%. None of the county is in drought on the October 13, 2026 Drought Monitor map.

FEMA's flood data list 85 flood losses here since 2016, 65% of them in buildings with basements. 53% of homes were built before 1980, against 50% nationally; the median home dates from 1976.

Data as of October 13, 2026 · sources

0%

expansive clay: shrink-swell limits slab homes

3%

high water table: limits basements

0%

in drought, October 13, 2026

53%

of homes built before 1980

Soil under Arlington County

Expansive clay (limits slab homes)0.0%
High water table (limits basements)2.9%
Septic fields very limited16.2%
Clay swell (LEP, by area)1.5%
High-swell land (LEP 6%+)0.0%
Urban land, not rated62.1%
Mapped soil16,700 acres
Soil seriesShare hereSeries nationally: expansive clay
Glenelg15%0%
Sassafras7%n/a
Manor2%n/a
Neabsco2%n/a
Codorusunder 1%n/a
Woodstownunder 1%n/a
Falls Church city: 0%Alexandria city: 3%District of Columbia: 0%Fairfax County: 6%Fairfax city: 2%Prince George's County: 1%Montgomery County: 1%Manassas Park city: 0%Arlington County Falls Church cityAlexandria cityDistrict of ColumbiaFairfaxFairfax cityPrince George'sMontgomeryManassas Park cityArlington
Arlington 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 VA013 (2025-09-05)

What the numbers mean here

Rain over the 12 months to August 2026: 33.15 in, 11.26 in below the 1991-2020 average year of 44.41 in.

With shrink-swell clay on 0% and a shallow water table on 3% of the land, the soil survey points to neither problem across most of Arlington 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 41 of the last 52 weeks; the most was 100% of its area, in 35 weeks, most recently on the July 28, 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 worse0%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

85 flood losses since 2016, $1.6 million paid. The worst year was 2019, with 47. Foundations of the buildings, where recorded: 65% basements, 11% slabs, 24% elevated. Median water depth outside the building: 12 in.

YearFlood losses
20161
20175
201817
201947
20204
20217
20220
20230
20241
20252
2026 to date1

Rain

Average year, 1991-202044.41 in
12 months to August 202633.15 in (-11.26)
202536.28 in (-8.13)
Wettest year since 18952018: 66.30 in
Driest year since 18951930: 20.10 in
Days with 1 inch or more, normal at WASHINGTON REAGAN AP (4 mi away)10

Homes

Housing units121,970
Median year built1976
Built before 198053%
Built 2000 or later27%
Owner-occupied41%
Median value, owner-occupied$895,000
Single-family detached25%

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
Falls Church city, VA 4 mi 0% 13%
Alexandria city, VA 4 mi 3% 44%
District of Columbia, DC 5 mi 0% 9%
Fairfax County, VA 10 mi 6% 33%
Fairfax city, VA 11 mi 2% 10%
Prince George's County, MD 14 mi 1% 46%
Montgomery County, MD 19 mi 1% 19%
Manassas Park city, VA 20 mi 0% 16%

Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status