Ohio / Van Wert County
Score 76 · high · #3 of 88 in OH
Crawl space moisture in Van Wert County, OH
97% of Van Wert County's mapped soil is somewhat poorly to very poorly drained, which means ground that stays wet near the surface for significant periods. Where a seasonal water table is reported — 99% of acres — it averages 0.6 ft below grade, shallow enough to reach a typical crawl-space footing.
- 1Water table 0.6 ft
- 2Wet soils 97%
- 3Moisture score 76
- 4EPA radon zone 1
Reading the Van Wert County soil survey
The score of 76 combines four parts, each from the USDA survey: wet drainage classes contribute 88.3 points of 100 on their own scale, group D soils 72.7, a shallow water table 90.4, and flooding 2.9; the weights are on the methodology page. The dominant hydrologic group is C/D (64% of acres): D when undrained, C when drained.
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 Van Wert County. Venting cannot fix that; it needs drainage — a perimeter drain to daylight or a sump — before any liner goes down.
Van Wert County against the rest of Ohio
Van Wert County ranks 3 of 88 Ohio counties, 30 points above the state median of 46. Only 2 other counties in the state score higher. Statewide, 44% of mapped soil is in the wet drainage classes; here it is 97%, half again the state figure or more. After very poorly drained, the next most common class is somewhat poorly drained at 28%.
Flooding. 2.9% 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 a high county, the model-code default of a vented crawl space over bare earth works against the soil: outside air brings humidity in all summer, and the ground underneath keeps supplying moisture from below. The R408 alternative — an unvented crawl space with a sealed vapor retarder lapped 6 inches and turned 6 inches up the stem wall, plus conditioned or exhaust air at 1 cfm per 50 sq ft or a dehumidifier — is built for exactly this. If the water table is shallow, drainage comes first.
Radon. Van Wert County is in EPA radon zone 1, the highest predicted potential. A sealed crawl space and a radon system share most of their parts — the liner, the sealed seams, a fan — so if you are encapsulating, test for radon first and design both together. EPA itself says the zone map is not a reason to skip testing in zones 2 and 3.
Near Van Wert County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area OH161; drainage covers 100% of 262,650 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.