Texas / Van Zandt County
Score 34 · moderate · #30 of 209 in TX
Crawl space moisture in Van Zandt County, TX
65% of Van Zandt 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 — 56% of acres — it averages 2.8 ft below grade.
- 1Water table 2.8 ft
- 2Wet soils 18%
- 3Moisture score 34
- 4EPA radon zone 3
Reading the Van Zandt County soil survey
The score of 34 combines four parts, each from the USDA survey: wet drainage classes contribute 23.9 points of 100 on their own scale, group D soils 58.3, a shallow water table 31.9, and flooding 15.6; the weights are on the methodology page. The dominant hydrologic group is D (39% of acres): very slow infiltration, high runoff (clays, high water table).
At 2.8 ft the seasonal water table is usually below a crawl-space floor, but the 56% 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.
Van Zandt County against the rest of Texas
Van Zandt County ranks 30 of 209 Texas counties, 16 points above the state median of 18. That puts it in the wettest quarter of the state. Statewide, 6% of mapped soil is in the wet drainage classes; here it is 18%, half again the state figure or more. After well drained, the next most common class is moderately well drained at 32%.
Flooding. 15.4% of acres with a flooding class are rated frequent; 0.4% of acres with a flooding class are rated occasional. 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 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 Van Zandt County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area TX467; drainage covers 99% of 549,964 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.