New York: basement moisture and foundation risk by county

62 counties, ranked by our combined index. Highest combined risk is Monroe County (75), lowest is Cortland County (29). The worst soil for foundation cracks specifically is in Wayne County.

Values from USDA NRCS SSURGO where available, otherwise our regional model — each county page states which. Methodology.

The physiographic regions inside New York

State lines are political; soil follows geology. These are the distinct ground types inside New York and why each behaves the way it does.

Glaciated New England upland

A hardpan under thin till creates a perched water table — water stands above an impermeable layer even though the regional water table is deep. It is the commonest cause of a wet basement in New England. Expansive clay is largely absent.

32 counties: Albany County, Chenango County, Clinton County, Columbia County, Cortland County, Dutchess County, Essex County, Franklin County, Fulton County, Genesee County, Greene County, Hamilton County, Herkimer County, Jefferson County, Lewis County, Madison County, Montgomery County, Niagara County, Oneida County, Orange County, Orleans County, Otsego County, Putnam County, Rensselaer County, Rockland County, Saratoga County, Schenectady County, Schoharie County, St. Lawrence County, Ulster County, Warren County, Washington County

Appalachian Plateau

Water travels over bedrock under a thin skin of colluvium. A house cut into a hillside has an entire catchment behind its uphill wall — what decides the outcome here is a daylight drain, not a coating.

18 counties: Allegany County, Broome County, Cattaraugus County, Cayuga County, Chautauqua County, Chemung County, Delaware County, Erie County, Livingston County, Ontario County, Schuyler County, Seneca County, Steuben County, Sullivan County, Tioga County, Tompkins County, Wyoming County, Yates County

Atlantic coastal plain

Extremely variable over short distances: sand and saturated clay side by side. A county figure means less here than anywhere else we cover — the individual parcel decides.

7 counties: Bronx County, Kings County, Nassau County, New York County, Queens County, Richmond County, Suffolk County

Glaciolacustrine lake plain

About the least favourable ground for a basement anywhere in the United States. Dead flat, clay with almost no permeability, and historically wetland that was drained artificially. Basements exist here because the houses were built before anyone modelled the consequence.

4 counties: Monroe County, Onondaga County, Oswego County, Wayne County

Piedmont

Saprolite is weathered rock that keeps its structure, so water moves through it along relict joints unpredictably. The Triassic basins inside the Piedmont are islands of strongly expansive clay.

1 counties: Westchester County

Page data updated 2026-08-12