HomeSouth CarolinaCharleston County

Charleston County, South Carolina

A shallow water table limits basements on 81% of Charleston County's mapped land, a higher share than 89% of US counties. Shrink-swell clay limits houses without basements on 0%.

13.6% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 3,957 flood losses here since 2016, 4% of them in buildings with basements. 35% of homes were built before 1980, against 50% nationally; the median home dates from 1991.

Data as of October 13, 2026 · sources

0%

expansive clay: shrink-swell limits slab homes

81%

high water table: limits basements

14%

in drought, October 13, 2026

35%

of homes built before 1980

Soil under Charleston County

Expansive clay (limits slab homes)0.0%
High water table (limits basements)80.6%
Septic fields very limited87.8%
Clay swell (LEP, by area)1.6%
High-swell land (LEP 6%+)0.0%
Urban land, not rated2.6%
Mapped soil669,300 acres
Soil seriesShare hereSeries nationally: high water table
Bohicket18%n/a
Rutlege8%n/a
Wadmalaw6%n/a
Yonges6%n/a
Foxworth5%n/a
Capers5%n/a
Berkeley County: 99%Dorchester County: 95%Colleton County: 92%Beaufort County: 77%Georgetown County: 87%Williamsburg County: 99%Clarendon County: 78%Orangeburg County: 77%Charleston County BerkeleyDorchesterColletonBeaufortGeorgetownWilliamsburgClarendonOrangeburgCharleston
Charleston 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 SC690 (2025-09-03)

What the numbers mean here

On 81% of Charleston 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: 28.70 in, 21.44 in below the 1991-2020 average year of 50.14 in.

USDA rates 88% of the land very limited for septic absorption fields.

Drought

13.6% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 40 of the last 52 weeks; the most was 100% of its area, in 38 weeks, most recently on the September 29, 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 worse13.6%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

3,957 flood losses since 2016, $88.1 million paid. The worst year was 2017, with 1,578. Foundations of the buildings, where recorded: 4% basements, 27% slabs, 33% crawl spaces, 35% elevated. Median water depth outside the building: 12 in.

YearFlood losses
20161,462
20171,578
2018119
201963
202086
202141
2022141
2023295
2024142
202524
2026 to date6

Rain

Average year, 1991-202050.14 in
12 months to August 202628.70 in (-21.44)
202541.93 in (-8.21)
Wettest year since 18951964: 73.06 in
Driest year since 18951931: 31.14 in
Days with 1 inch or more, normal at CHARLESTON CITY (2 mi away)12.4

Homes

Housing units209,803
Median year built1991
Built before 198035%
Built 2000 or later39%
Owner-occupied64%
Median value, owner-occupied$489,100
Single-family detached58%

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
Berkeley County, SC 28 mi 2% 99%
Dorchester County, SC 33 mi 0% 95%
Colleton County, SC 42 mi 5% 92%
Beaufort County, SC 53 mi 32% 77%
Georgetown County, SC 57 mi 12% 87%
Williamsburg County, SC 59 mi 0% 99%
Clarendon County, SC 62 mi 0% 78%
Orangeburg County, SC 66 mi 0% 77%

Sources: USDA SSURGO (September 3, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status