Pennsylvania / Greene County
Score 50 · elevated · #4 of 67 in PA
Crawl space moisture in Greene County, PA
92% of Greene 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 — 91% of acres — it averages 2.4 ft below grade.
- 1Water table 2.4 ft
- 2Wet soils 7%
- 3Moisture score 50
- 4EPA radon zone 2
Reading the Greene County soil survey
The score of 50 combines four parts, each from the USDA survey: wet drainage classes contribute 33 points of 100 on their own scale, group D soils 87.5, a shallow water table 57.8, and flooding 6; the weights are on the methodology page. The dominant hydrologic group is D (80% of acres): very slow infiltration, high runoff (clays, high water table).
At 2.4 ft the seasonal water table is usually below a crawl-space floor, but the 91% 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.
Greene County against the rest of Pennsylvania
Greene County ranks 4 of 67 Pennsylvania counties, 25 points above the state median of 25. That puts it in the wettest quarter of the state. Statewide, 16% of mapped soil is in the wet drainage classes; here it is 7%, below the state figure — the score here comes from heavy group D soils rather than drainage class alone. After moderately well drained, the next most common class is well drained at 9%.
Flooding. 5.5% of acres with a flooding class are rated frequent; 0.8% 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 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 2. The zone is a county-level prediction; EPA says elevated levels occur in every zone and every home should be tested.
Near Greene County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area PA059; drainage covers 99% of 369,789 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.