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Johnston County, North Carolina

A shallow water table limits basements on 74% of Johnston County's mapped land, a higher share than 84% of US counties. Shrink-swell clay limits houses without basements on 1%.

100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 193 flood losses here since 2016, 8% of them in buildings with basements. 22% of homes were built before 1980, against 50% nationally; the median home dates from 2000.

Data as of October 13, 2026 · sources

1%

expansive clay: shrink-swell limits slab homes

74%

high water table: limits basements

100%

in drought, October 13, 2026

22%

of homes built before 1980

Soil under Johnston County

Expansive clay (limits slab homes)1.4%
High water table (limits basements)74.3%
Septic fields very limited63.4%
Clay swell (LEP, by area)1.8%
High-swell land (LEP 6%+)1.4%
Mapped soil510,137 acres
Soil seriesShare hereSeries nationally: high water table
Norfolk11%63%
Gilead8%n/a
Goldsboro7%n/a
Rains7%n/a
Wehadkee5%n/a
Bibb5%n/a
Wayne County: 70%Wake County: 32%Wilson County: 86%Harnett County: 62%Sampson County: 80%Nash County: 64%Greene County: 83%Franklin County: 21%Johnston County WayneWakeWilsonHarnettSampsonNashGreeneFranklinJohnston
Johnston 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 NC101 (2025-08-27)

What the numbers mean here

On 74% of Johnston 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: 33.15 in, 15.77 in below the 1991-2020 average year of 48.92 in.

USDA rates 63% 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 52 of the last 52 weeks; the most was 100% of its area, in 50 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 worse67.6%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

193 flood losses since 2016, $9.2 million paid. The worst year was 2016, with 120. Foundations of the buildings, where recorded: 8% basements, 28% slabs, 43% crawl spaces, 22% elevated. Median water depth outside the building: 23 in.

YearFlood losses
2016120
201714
201813
20197
202025
20214
20221
20232
20243
20252
2026 to date2

Rain

Average year, 1991-202048.92 in
12 months to August 202633.15 in (-15.77)
202545.72 in (-3.20)
Wettest year since 18952020: 66.17 in
Driest year since 18952007: 32.77 in
Days with 1 inch or more, normal at SMITHFIELD (1 mi away)13.8

Homes

Housing units91,218
Median year built2000
Built before 198022%
Built 2000 or later50%
Owner-occupied76%
Median value, owner-occupied$305,600
Single-family detached76%

What repairs cost

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

WorkRangeSource
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

PlaceDistanceExpansive clayHigh water table
Wayne County, NC 23 mi 1% 70%
Wake County, NC 25 mi 4% 32%
Wilson County, NC 28 mi under 1% 86%
Harnett County, NC 30 mi under 1% 62%
Sampson County, NC 36 mi 0% 80%
Nash County, NC 38 mi 1% 64%
Greene County, NC 39 mi 0% 83%
Franklin County, NC 40 mi 8% 21%

Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status