Score 20 · moderate · #25 of 46 in SC

Crawl space moisture in Kershaw County, SC

Kershaw County scores moderate: no single wet-soil signal dominates its mapped acres. Where a seasonal water table is reported — 38% of acres — it averages 2 ft below grade.

Size venting or encapsulation

1Water table 2 ft
2Wet soils 13%
3Moisture score 20
4EPA radon zone 3

Share of mapped soil acres in Kershaw County, SC by NRCS drainage class (dominant condition), bars to scale; wetter classes highlighted. Covers 100% of mapped acres.

Dominant drainage

Well drained

38% of acres

Group D soils

23%

slow infiltration

Flood-prone acres

12%

any flooding frequency

Ponding

acres where water ponds

Reading the Kershaw County soil survey

The score of 20 combines four parts, each from the USDA survey: wet drainage classes contribute 18.7 points of 100 on their own scale, group D soils 19.8, a shallow water table 25.9, and flooding 12.1; the weights are on the methodology page. The dominant hydrologic group is A (38% of acres): high infiltration, low runoff (sands, gravels).

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

At 2 ft the seasonal water table is usually below a crawl-space floor, but the 38% 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.

Kershaw County against the rest of South Carolina

Kershaw County ranks 25 of 46 South Carolina counties, 5 points below the state median of 25. That places it in the middle range, nationally and for the state. Statewide, 34% of mapped soil is in the wet drainage classes; here it is 13%, below the state figure — the score here comes from flooding and ponding rather than drainage class alone. After well drained, the next most common class is excessively drained at 27%.

Flooding. 12% of acres with a flooding class are rated frequent; 0.2% of acres with a flooding class are rated occasional. 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 a moderate county the soil record is mixed rather than uniformly wet, so conditions vary from lot to lot. Where the lot drains, the model-code default — a vented crawl space with 1 sq ft of net vent per 150 sq ft of floor, or 1 per 1500 with a Class I vapor retarder on the ground — is a reasonable starting point; where the sections above point to a shallow water table or flood-prone soil on your lot, plan as for an elevated county. Either way, check the site first: grading that falls away from the foundation, gutters and downspouts that discharge well clear of it, and a ground cover over bare earth. A wet crawl space in a moderate county points to one of those 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 Kershaw County by score

York County 20 Chesterfield County 22Calhoun County 16Union County 16

All 46 South Carolina counties

Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area SC610; drainage covers 100% of 473,100 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.