Virginia / Southampton County
Score 43 · elevated · #10 of 95 in VA
Crawl space moisture in Southampton County, VA
Southampton County scores elevated because several moderate signals stack up rather than one dominant one. Where a seasonal water table is reported — 96% of acres — it averages 2.2 ft below grade.
- 1Water table 2.2 ft
- 2Wet soils 30%
- 3Moisture score 43
- 4EPA radon zone 3
Reading the Southampton County soil survey
The score of 43 combines four parts, each from the USDA survey: wet drainage classes contribute 42 points of 100 on their own scale, group D soils 34.2, a shallow water table 63.5, and flooding 19.7; the weights are on the methodology page. The dominant hydrologic group is C (45% of acres): slow infiltration (clay layers).
At 2.2 ft the seasonal water table is usually below a crawl-space floor, but the 96% of acres that report one are by definition the wettest parts of the county; on those lots, a wet spring can bring water close to the footings.
Southampton County against the rest of Virginia
Southampton County ranks 10 of 95 Virginia counties, 31 points above the state median of 12. That puts it in the wettest quarter of the state. Statewide, 11% of mapped soil is in the wet drainage classes; here it is 30%, half again the state figure or more. After moderately well drained, the next most common class is well drained at 26%.
Flooding. 15.1% of acres with a flooding class are rated frequent; 3.8% of acres with a flooding class are rated occasional; 10% of acres with a flooding class are rated rare; 1.9% 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. Ponding — water standing at the surface with nowhere to go — affects 7.7% of acres.
What it means for a crawl space here
In an elevated county the soil supplies more moisture than average, but a vented crawl space can work if the ground is covered: the code lets vent area drop from 1 sq ft per 150 to 1 per 1500 with a Class I vapor retarder on the ground, which is an admission of how much moisture comes from below. Grading, gutters and a ground cover usually decide whether a crawl space here stays dry before any decision about sealing it.
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 Southampton County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area VA175; drainage covers 99% of 390,800 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.