First, flood-plain zoning focuses on “high-risk” areas, which by definition means areas in the 100-year floodplain. Fannie Mae and Freddie Mac require that homes they mortgage be covered by flood insurance if they are in zone A or V, which means the 100-year floodplain.
But the Houston flooding resulting from tropical storm Harvey was a 1,000-year flood. That means neither zoning nor insurance would have made a difference for the homes outside the 100-year floodplain. At least half of all the homes damaged by Harvey flooding were in the “moderate-risk” zone in the 500-year floodplain but outside the 100-year floodplain, and more were in the low-risk area outside the 500-year floodplain. Continue reading