States / New Jersey
21 counties · median score 30
Crawl space moisture in New Jersey
Most of New Jersey drains well: only 3 of 21 counties score high or elevated, and the median is 30. Cape May County is the exception at 53; crawl-space moisture problems here usually come from grading, gutters and plumbing rather than the soil itself.
- 1Wettest county Cape May County
- 2High or elevated 3 of 21
- 3Median score 30
- 4Driest county Bergen County
New Jersey's soil, taken as a whole
Across the 5,022,678 acres mapped in these 21 counties, 30% of soil with a drainage class is somewhat poorly, poorly or very poorly drained, and 48% of acres report a seasonal water table within about two metres. That is a wet state by any measure; a third or more of its land holds water near the surface for part of the year. 20 of the 21 counties have mapped soils subject to occasional or frequent flooding.
| Drainage class | Share of mapped acres |
|---|---|
| Excessively drained | 5.9% |
| Somewhat excessively drained | 5.9% |
| Well drained | 41.4% |
| Moderately well drained | 16.4% |
| Somewhat poorly drained | 6.8% |
| Poorly drained | 9% |
| Very poorly drained | 12.1% |
| Subaqueous | 2.5% |
Radon. By EPA zone, 7 New Jersey counties here are zone 1 (highest potential), 11 zone 2 and 3 zone 3. EPA says to test regardless of zone; a sealed crawl space is the cheapest moment to add radon venting if a test calls for it.
Every New Jersey county
Sorted wettest first. High and elevated counties link to their own page with the full soil breakdown.
What drives the New Jersey numbers
The wettest county, Cape May County, is 53% very poorly drained by dominant condition, with a seasonal water table averaging 1.4 ft below grade across the 76% of acres that report one, and sits in EPA radon zone 3. The driest, Bergen County, is 65% well drained. No New Jersey county reaches the high tier.
The score is a guide to the soil, not to a house: a well-graded lot with working gutters in a high county can have a dry crawl space, and a bad downspout can flood one in a low county. The R408 calculator sizes venting or encapsulation for any footprint.
Sources: USDA NRCS SSURGO via Soil Data Access (muaggatt: drclassdcd, hydgrpdcd, flodfreqdcd, pondfreqprs, wtdepannmin), acreage-weighted; EPA Map of Radon Zones, county table (June 2024 JSON). Checked 2026-10-23.