The Long Road to Adoption: How Long Does it Take to Adopt Updated County‐Level Flood Insurance Rate Maps?

Abstract

Floods cause the most damage of all natural disasters in the United States. Households and communities receive much of their information on flood hazards from maps produced by the Federal Emergency Management Agency (FEMA). These maps have been criticized for many reasons: they use poor data, do not reflect a changing climate, do not capture rainfall flooding, create misperceptions about risk, and are often out of date. We examine this last concern, investigating how long it takes updated county‐level flood maps to be adopted across the country, using a unique nationwide data set from June 2014 to 2017. We find substantial heterogeneity in the time to adopt maps, with multiple outliers where the process far exceeds the time FEMA has estimated should be standard. Many factors may generate delay, including time for new data collection, technical challenges to revised maps, and community opposition. We also find there are differences in appeal rates and the timing of map revisions based on those appeals between inland and coastal counties and between higher and lower income communities. These correlations raise important questions for policymakers and scholars about the equity and accuracy of the nation's current approach to mapping changing flood risk.