States / New York
62 counties · median score 39
Crawl space moisture in New York
New York is mixed: 27 of 62 counties score high or elevated, concentrated where drainage is poorest — Niagara County tops the list at 60 — while New York County scores just 4. Where you are in the state matters more than the state itself.
- 1Wettest county Niagara County
- 2High or elevated 27 of 62
- 3Median score 39
- 4Driest county New York County
New York's soil, taken as a whole
Across the 31,354,142 acres mapped in these 62 counties, 28% of soil with a drainage class is somewhat poorly, poorly or very poorly drained, and 60% of acres report a seasonal water table within about two metres. That is a middling figure: wet ground is common in valleys and lowlands but far from universal. 60 of the 62 counties have mapped soils subject to occasional or frequent flooding.
| Drainage class | Share of mapped acres |
|---|---|
| Excessively drained | 3.2% |
| Somewhat excessively drained | 7.4% |
| Well drained | 40.2% |
| Moderately well drained | 20.7% |
| Somewhat poorly drained | 17.3% |
| Poorly drained | 5.7% |
| Very poorly drained | 5.5% |
Radon. By EPA zone, 34 New York counties here are zone 1 (highest potential), 13 zone 2 and 15 zone 3. With most of the state in zone 1, any crawl-space sealing project here should start with a radon test and be designed to take a radon fan.
Every New York county
Sorted wettest first. High and elevated counties link to their own page with the full soil breakdown.
What drives the New York numbers
The wettest county, Niagara County, is 47% somewhat poorly drained by dominant condition, with a seasonal water table averaging 0.9 ft below grade across the 89% of acres that report one, and sits in EPA radon zone 2. The driest, New York County, is 98% well drained. 1 New York counties reach the high tier, where poorly drained soils, group D clays and a shallow water table occur together.
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.