Yolo County, CA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Yolo County scores at the 89.6th percentile for flood hazard, rated "Relatively Moderate" — a middling flood hazard by national standards. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about once every 1 years. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Mandatory flood insurance compliance in Yolo County
Homes with a federally backed mortgage inside Yolo County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 28.1% of them do — 854 active policies against 3,036 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 5% of all residential structures in Yolo County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Yolo County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Yolo County ranks 342 — 1 being the highest hazard nationally — and 319 by population among all 3144 counties covered here, where 1 is the largest. Yolo County, California covers 1,012.988 square miles and counts roughly 225,251 residents.
Checking a specific address in Yolo County
Across all of Yolo County's 52,448 residential structures, 2,606 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Yolo County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.