Crawl space moisture in Surry County, VA

55% of Surry County's soil falls in hydrologic group D or a dual D group: clays and high water tables that shed water slowly. Where a seasonal water table is reported — 88% of acres — it averages 1.9 ft below grade, shallow enough to reach a typical crawl-space footing.

Size venting or encapsulation

1Water table 1.9 ft
2Wet soils 27%
3Moisture score 47
4EPA radon zone 3

Share of mapped soil acres in Surry County, VA by NRCS drainage class (dominant condition), bars to scale; wetter classes highlighted. Covers 89% of mapped acres.

Dominant drainage

Moderately well drained

59% of acres

Group D soils

55%

slow infiltration

Flood-prone acres

11%

any flooding frequency

Ponding

acres where water ponds

Reading the Surry County soil survey

The score of 47 combines four parts, each from the USDA survey: wet drainage classes contribute 43.6 points of 100 on their own scale, group D soils 52.4, a shallow water table 62.5, and flooding 10.9; the weights are on the methodology page. The dominant hydrologic group is C (30% of acres): slow infiltration (clay layers).

Hydrologic soil groups in Surry 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 Surry County. Venting cannot fix that; it needs drainage — a perimeter drain to daylight or a sump — before any liner goes down.

Surry County against the rest of Virginia

Surry County ranks 8 of 95 Virginia counties, 35 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 27%, half again the state figure or more. After moderately well drained, the next most common class is poorly drained at 18%.

Flooding. 9.7% of acres with a flooding class are rated frequent. Flood-prone soils are a minority here, concentrated along streams; the score mostly reflects what happens between floods.

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 Surry County by score

New Kent County 47 Sussex County 47 Greensville County 49 Isle of Wight County 50

All 95 Virginia counties

Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area VA181; drainage covers 89% of 198,500 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.