Score 75 · high · #1 of 100 in NC

Crawl space moisture in Currituck County, NC

89% of Currituck County's mapped soil is somewhat poorly to very poorly drained, which means ground that stays wet near the surface for significant periods. Where a seasonal water table is reported — 73% of acres — it averages 0.3 ft below grade, shallow enough to reach a typical crawl-space footing.

Size venting or encapsulation

1Water table 0.3 ft
2Wet soils 89%
3Moisture score 75
4EPA radon zone 3

Share of mapped soil acres in Currituck County, NC by NRCS drainage class (dominant condition), bars to scale; wetter classes highlighted. Covers 76% of mapped acres.

Dominant drainage

Subaqueous

36% of acres

Group D soils

90%

slow infiltration

Flood-prone acres

61%

any flooding frequency

Ponding

acres where water ponds

Reading the Currituck County soil survey

The score of 75 combines four parts, each from the USDA survey: wet drainage classes contribute 89.2 points of 100 on their own scale, group D soils 70.7, a shallow water table 69.7, and flooding 43; the weights are on the methodology page. The dominant hydrologic group is D (41% of acres): very slow infiltration, high runoff (clays, high water table).

Hydrologic soil groups in Currituck County by share of acres, columns to scale. Group D and dual groups (x/D) shed water slowly and hold it near the surface.

A water table under two feet is the single most important number here. A crawl-space floor is usually 18 to 36 inches below the joists and often below outside grade, so in a wet season groundwater can stand at or above the crawl-space floor across much of Currituck County. Venting cannot fix that; it needs drainage — a perimeter drain to daylight or a sump — before any liner goes down.

Currituck County against the rest of North Carolina

Currituck County ranks 1 of 100 North Carolina counties, 58 points above the state median of 17. Only no other county in the state scores higher. Statewide, 30% of mapped soil is in the wet drainage classes; here it is 89%, half again the state figure or more. After subaqueous, the next most common class is very poorly drained at 33%.

Flooding. 3.4% of acres with a flooding class are rated frequent; 0.4% of acres with a flooding class are rated occasional; 21.7% of acres with a flooding class are rated rare; 0.3% of acres with a flooding class are rated very rare. That is a large flood-prone share; a crawl space in the floodplain needs flood vents under most local floodplain ordinances, which is a separate rule from R408 and can rule out a fully sealed design.

What it means for a crawl space here

In a high county, the model-code default of a vented crawl space over bare earth works against the soil: outside air brings humidity in all summer, and the ground underneath keeps supplying moisture from below. The R408 alternative — an unvented crawl space with a sealed vapor retarder lapped 6 inches and turned 6 inches up the stem wall, plus conditioned or exhaust air at 1 cfm per 50 sq ft or a dehumidifier — is built for exactly this. If the water table is shallow, drainage comes first.

Radon. EPA radon zone 3. The zone is a county-level prediction; EPA says elevated levels occur in every zone and every home should be tested.

Near Currituck County by score

Tyrrell County 72 Camden County 71 Washington County 71 Beaufort County 70

All 100 North Carolina counties

Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area NC053; drainage covers 76% of 336,232 mapped acres); EPA Map of Radon Zones, county table (June 2024 JSON); IRC R408.3 Unvented crawl space, as adopted in S.C. Code Regs. 8-1221 (LII). Checked 2026-10-23.