Hillsborough substantial damage and substantial improvement in flood hazard areas

For structures in a Special Flood Hazard Area, additions, repairs, reconstruction, and other improvements can trigger Hillsborough's substantial-improvement or substantial-damage review. County guidance uses the FEMA 50-percent framework. Substantial Improvement Worksheets are required for all projects within the SFHA, unless an approved FEMA Elevation Certificate documents that the building is properly elevated and conforms to flood-resistant construction requirements. The relevant value is the building/structure market value, not the land value. If damage or planned improvement meets the substantial threshold, the structure may need to be brought into current floodplain compliance. StartFL should never calculate a final substantial-damage determination from assessed parcel value alone; use the County's current worksheet, HCPA structure-value method or qualified appraisal, project costs, and permit history.