New Jersey / Ocean County
Score 43 · elevated · #3 of 21 in NJ
Crawl space moisture in Ocean County, NJ
Ocean County scores elevated because several moderate signals stack up rather than one dominant one. Where a seasonal water table is reported — 64% of acres — it averages 1.4 ft below grade, shallow enough to reach a typical crawl-space footing.
- 1Water table 1.4 ft
- 2Wet soils 42%
- 3Moisture score 43
- 4EPA radon zone 3
Reading the Ocean County soil survey
The score of 43 combines four parts, each from the USDA survey: wet drainage classes contribute 46.5 points of 100 on their own scale, group D soils 32.9, a shallow water table 50.2, and flooding 32.7; the weights are on the methodology page. The dominant hydrologic group is A (53% of acres): high infiltration, low runoff (sands, gravels).
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 Ocean County. Venting cannot fix that; it needs drainage — a perimeter drain to daylight or a sump — before any liner goes down.
Ocean County against the rest of New Jersey
Ocean County ranks 3 of 21 New Jersey counties, 13 points above the state median of 30. Only 2 other counties in the state score higher. Statewide, 30% of mapped soil is in the wet drainage classes; here it is 42%. After well drained, the next most common class is very poorly drained at 19%.
Flooding. 9.6% of acres with a flooding class are rated frequent; 1.5% of acres with a flooding class are rated occasional; 2.9% 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 Ocean County by score
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted (survey area NJ029; drainage covers 98% of 483,200 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.