St. Louis city, MO: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, St. Louis city scores at the 97th percentile for flood hazard, rated "Relatively High" — well above the national norm for flood hazard. 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 1.3 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
St. Louis city's flood-insurance compliance gap
FEMA hasn't published a residential structure count for St. Louis city's mapped flood zone, so a reliable mandatory-compliance percentage can't be computed here — see the data quality guide for why this gap exists for roughly a quarter of US counties. Looking beyond the mandated zone, 0.1% of all residential structures in St. Louis city carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where St. Louis city ranks
Among the 3144 US counties FEMA scores for flood hazard, St. Louis city ranks 105 — 1 being the highest hazard nationally — and 261 by population among all 3144 counties covered here, where 1 is the largest. St. Louis city, Missouri covers 61.717 square miles and counts roughly 279,695 residents.
Checking a specific address in St. Louis city
135 of St. Louis city's 97,837 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where St. Louis city's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. St. Louis city's compliance figure is one of the ones affected by FEMA's incomplete denominator data — the data quality guide explains what that means and how many counties it touches.