Suffolk County, NY flood risk explained
Flood hazard in Suffolk County sits at the 98.6th national percentile, among the highest flood hazard in the country; split between inland river flooding (about 3.5 times a year) and coastal storm surge (about 3.8 times a year). This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Suffolk County's flood-insurance compliance gap
Out of 21,119 homes FEMA counts inside Suffolk County's mapped flood zone, 13,883 carry the flood policy federal law requires there — 65.7% compliance, short of full coverage. Looking beyond the mandated zone, 5.4% of all residential structures in Suffolk County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Suffolk County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Suffolk County ranks 49 — 1 being the highest hazard nationally — and 27 by population among all 3144 counties covered here, where 1 is the largest. Suffolk County, New York is home to about 1,535,909 people across 910.94 square miles of land.
What to do next if you own or are buying in Suffolk County
26,160 of Suffolk County's 487,590 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Suffolk County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Suffolk County's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.