Flood Risk and Flood Insurance by County
GAO-27-108012, October 1, 2026
Floods are the most common and destructive type of natural disaster in the United States, yet many property owners don't have flood insurance.
The Federal Emergency Management Agency (FEMA) administers the National Flood Insurance Program (NFIP), which accounts for the majority of flood insurance policies. Property owners in areas that FEMA designates as special flood hazard areas (SFHAs) and who have federally backed mortgages are generally required to purchase flood insurance.
However, substantial flood damage occurs outside of these areas. Property owners who are not required to purchase flood insurance may not do so for several reasons. For example, they may underestimate their risk or not realize floods are excluded from their homeowners insurance. Property owners may also overestimate the benefit of federal disaster assistance.
This interactive map uses data from both FEMA and First Street, a private climate modeler which provides property-level flood risk data. (First Street data includes heavy rainfall in their flood risk modeling, which may provide a more accurate risk calculation than FEMA's flood maps.)
We break this data down using the following categories:
- High-Risk Properties (FEMA): Percentage of properties in a county that are in an SFHA as of January 2024
- High-Risk Properties (First Street): Percentage of properties in a county that meet the SFHA threshold as of January 2024, according to First Street
- High-Risk Properties (FEMA) with an NFIP Policy: Estimated percentage of properties in a county that are in an SFHA that have an NFIP policy as of April 2026
- High-Risk Properties (First Street) with an NFIP Policy: Estimated percentage of properties in a county with high flood risk that have an NFIP policy as of April 2026, according to First Street
- All Properties with an NFIP Policy: Estimated percentage of properties in a county with an NFIP policy as of April 2026
- NFIP Policies with Discounted Premiums: Percentage of NFIP policies in a county with premiums that do not fully reflect their flood risk as of April 2026
This interactive map displays data in two ways:
1. Select a specific category and the map will display the information by color.
2. Hover the cursor over a particular county (regardless of the selected category) and you'll see a pop-up window with all the information about that county.
Notes:
Source: GAO analysis of FEMA and First Street data.
Notes: Several private flood models exist, each with varying estimates of flood risk. We determined that First Street's flood model best met our needs and was reliable for the purposes of our analyses. Calculating the percentage of high-risk properties with NFIP coverage required matching NFIP data to First Street data. We accounted for unmatched contracts by dividing the matched coverage rate by the county match rate.
For more information, read our report, GAO-27-108012.