Duluth, MN Environmental Rules: Flood Elevation Requirements (2026)

The Natural Resources Overlay in the Unified Development Chapter (Chapter 50) ties every floodplain elevation requirement to the Base Flood Elevation (BFE) shown on FEMA's Flood Insurance Rate Maps. The baseline standard is the Regulatory Flood Protection Elevation (RFPE), the height above which utilities, mechanical equipment and, in the Flood Fringe District, a structure's lowest floor must sit. For fill-supported residential structures in the Flood Fringe District, the code only allows this construction method where the natural ground is no lower than three feet below the base flood elevation, and the fill itself must hold the same elevation for at least 15 feet beyond the structure's outside limits, certified by a registered professional engineer, land surveyor or other qualified person the building official designates.

2-percent-annual-chance flood elevation, whichever number is higher. Alternative elevation methods, such as piers, pilings or filled stem walls, are available for nonresidential structures but require certification by a professional engineer or architect and compliance with FEMA Technical Bulletin 1. All of this runs through the City of Duluth's own floodplain permit before construction starts.