The NFIP’s grandfathering provision (PDF) offers savings for structures that were built before a flood map was issued for the community, or that were built in compliance with the flood map in effect at the time of construction. The simplest way to grandfather is to purchase a flood insurance policy before the new map takes effect and maintain coverage without a lapse. Sometimes using the new zone can provide a better rate than using the older one, so property owner should always ask their agent to look at both options. Check with your insurance agent or local building official to determine if grandfathering is right for you.
How Grandfathering Works
If a policy is obtained before a new map becomes effective, policyholders can retain the rate associated with the previous map’s flood zone and BFE, as long as continuous coverage has been maintained. For structures built after a Flood Insurance Rate Map (FIRM) was issued, insurance costs will be based on the zone designation and BFE for the map in effect at the time the structure was built (unless the new map offers a lower rate).
However, policyholders must submit supporting documentation to their insurer that shows the structure was built to conform to standards on the earlier map. Continuous coverage is not required in this case. If a structure was built before the community’s first FIRM was issued and the policy was not purchased prior to the effective date of a new map, policyholders can still save, but policy costs will be defined by pre-FIRM rates associated with their zone designation on the new map.