San Diego County, CA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, San Diego County scores at the 99.7th percentile for flood hazard, rated "Very High" — among the highest flood hazard in the country. 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 7.9 times a year. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Who actually carries the flood insurance FEMA requires
24.2% of the homes FEMA requires to carry flood insurance in San Diego County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 3,137 policies against 12,953 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.7% of all residential structures in San Diego County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where San Diego County ranks
Among the 3144 US counties FEMA scores for flood hazard, San Diego County ranks 11 — 1 being the highest hazard nationally — and 5 by population among all 3144 counties covered here, where 1 is the largest. San Diego County, California covers 4,210.884 square miles and counts roughly 3,298,799 residents.
Checking a specific address in San Diego County
6,088 of San Diego County's 890,566 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where San Diego 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.