Arkansas / Ouachita County
Score 43 · elevated · #28 of 67 in AR
Crawl space moisture in Ouachita County, AR
Ouachita County scores elevated because several moderate signals stack up rather than one dominant one. Where a seasonal water table is reported — 69% of acres — it averages 2.1 ft below grade.
- 1Water table 2.1 ft
- 2Wet soils 41%
- 3Moisture score 43
- 4EPA radon zone 3
Reading the Ouachita County soil survey
The score of 43 combines four parts, each from the USDA survey: wet drainage classes contribute 44.8 points of 100 on their own scale, group D soils 41.9, a shallow water table 47.4, and flooding 28.2; the weights are on the methodology page. The dominant hydrologic group is C (29% of acres): slow infiltration (clay layers).
At 2.1 ft the seasonal water table is usually below a crawl-space floor, but the 69% 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.
Ouachita County against the rest of Arkansas
Ouachita County ranks 28 of 67 Arkansas counties, 9 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 41%. After well drained, the next most common class is poorly drained at 41%.
Flooding. 28.1% of acres with a flooding class are rated frequent; 0.2% of acres with a flooding class are rated occasional; 0.1% 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 Ouachita County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area AR103; drainage covers 98% of 473,556 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.