How much flood risk does Mason County actually carry?
Mason County lands at the 25.4th percentile of FEMA's National Risk Index for flooding, "Very Low" territory — among the lowest flood hazard in the country — with the hazard 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.
Who actually carries the flood insurance FEMA requires
Mason County is one of the counties where FEMA's own denominator for mandated flood-zone structures is missing, so no compliance rate is shown rather than a guessed one — the data quality guide covers how common this is. Across all residential structures in Mason County, not just the ones FEMA mandates, 0.5% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Mason County against the rest of the country
Mason County sits at rank 2391 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2886 of 3144 by population (1 is biggest). About 3,987 people live in Mason County, Texas, spread over 928.836 square miles.
What to do next if you own or are buying in Mason County
Across all of Mason County's 1,846 residential structures, 9 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Mason County's numbers. See the data quality guide for why Mason County, like hundreds of other counties, doesn't get a clean compliance percentage.