Crawl space moisture in Sevier County, AR

50% of Sevier 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 — 66% of acres — it averages 2 ft below grade.

Size venting or encapsulation

1Water table 2 ft
2Wet soils 31%
3Moisture score 40
4EPA radon zone 3

Share of mapped soil acres in Sevier County, AR by NRCS drainage class (dominant condition), bars to scale; wetter classes highlighted. Covers 96% of mapped acres.

Dominant drainage

Well drained

38% of acres

Group D soils

50%

slow infiltration

Flood-prone acres

28%

any flooding frequency

Ponding

acres where water ponds

Reading the Sevier County soil survey

The score of 40 combines four parts, each from the USDA survey: wet drainage classes contribute 32.6 points of 100 on their own scale, group D soils 53.4, a shallow water table 45.7, and flooding 19; the weights are on the methodology page. The dominant hydrologic group is C (35% of acres): slow infiltration (clay layers).

Hydrologic soil groups in Sevier 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 66% 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.

Sevier County against the rest of Arkansas

Sevier County ranks 31 of 67 Arkansas counties, 6 points above the state median of 34. Wetter counties exist in Arkansas, but the soil here still sits well above the national middle. Statewide, 33% of mapped soil is in the wet drainage classes; here it is 31%, below the state figure — the score here comes from heavy group D soils rather than drainage class alone. After well drained, the next most common class is moderately well drained at 28%.

Flooding. 5.9% of acres with a flooding class are rated frequent; 21.8% of acres with a flooding class are rated occasional; 0.2% of acres with a flooding class are rated 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 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 Sevier County by score

Clark County 42 White County 42 Ouachita County 43 Sebastian County 37

All 67 Arkansas counties

Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area AR133; drainage covers 96% of 372,237 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.