Wayne County, IN Environmental Rules: Flood Elevation Requirements (2026)

Wayne County Code § 154.05 defines BASE FLOOD ELEVATION (BFE) as the elevation of the flood having a 1% annual chance of occurring, and defines FLOOD PROTECTION GRADE (FPG) as the elevation of the regulatory flood plus two feet at any given location in the SFHA, cross-referencing FREEBOARD, defined as a safety factor, usually expressed in feet above the BFE, applied to compensate for unknown factors that could push flood heights higher than calculated. Section 154.26(A) applies this protection requirement to new structures over 400 square feet, additions or improvements costing 50% or more of the existing structure's value, repairs to flood-damaged structures costing 50% or more of pre-damage market value, manufactured homes placed on new sites, and repetitive-loss structures.

Section 154.26(B) requires new construction or substantial improvement of any residential structure, or manufactured home, to have its lowest floor, including any basement, at or above the FPG, meaning two feet above the base flood elevation; where solid foundation perimeter walls elevate the structure, flood-vent openings meeting § 154.26(D)'s standards are required. Section 154.26(C) gives non-residential structures the same two-foot-above-BFE elevation option or lets them instead be dry flood-proofed to or above the FPG, certified by a registered professional engineer or architect under § 154.45(B)(12) that the structure is watertight below the FPG and can resist flood forces, effects of buoyancy and debris impact without human intervention or outside power.

Section 154.26(D) requires elevated structures with enclosed areas below the FPG to include at least two flood-vent openings in at least two exterior walls, sized to at least one square inch per square foot of enclosed area, with the bottom of each opening no more than one foot above grade.