What is substantial improvement and what does it mean?
Substantial improvement is any reconstruction, rehabilitation, addition, or improvement of a structure taking place during a 10-year period in which the cumulative percentage of improvements equals or exceeds 50% of the market value of the structure before the improvement or repair is started. If a building is substantially improved, the building must be brought into compliance with the floodplain regulations, which means the lowest floor, including the basement, must be elevated above the base flood elevation.

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1. Can I build in the floodplain?
2. Can I make home repairs or improvements in the floodplain?
3. What is substantial improvement and what does it mean?
4. What is substantial damage?
5. What types of flood hazard zones are shown on a Flood Insurance Rate Map?