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

Chapter 152 of the Dearborn County Code, adopted by the Board of Commissioners in Ord. 2005-8, sets the elevation standard in § 152.51 for every special flood hazard area (SFHA) in unincorporated Dearborn County, Indiana. The Flood Protection Grade (FPG) is defined in § 152.15 as the elevation of the regulatory flood plus two feet, and the same section ties the term to freeboard. For a home or manufactured home, § 152.51(B)(1) requires the lowest floor, including basement, at or above the FPG, printed as two feet above the base flood elevation. For commercial, industrial or other nonresidential buildings, § 152.51(C)(1) requires the lowest floor to be elevated to or above that same FPG.

The building protection requirement in § 152.51(A) reaches new structures with a floor area greater than 400 square feet, structural alterations that equal or exceed 50% of the value of the pre-altered structure, repairs to a damaged structure valued at more than 50% of its market value before the damage, work on a repetitive-loss structure, a manufactured home installed on a new site, and a travel trailer or recreational vehicle kept on a site for more than 180 days. Section 152.15 defines substantial improvement by the same 50% of market value test.

Nonresidential buildings in A Zones have one alternative. Under § 152.51(C)(2), a registered professional engineer or architect can certify that the structure is watertight below the FPG and able to resist the regulatory flood, and the measures must work without human intervention and without an outside source of electricity. The code prints no floodproofing option for residential buildings.

Other standards sit beside the elevation rule. Enclosed areas below the lowest floor must keep two openings with a net area of at least one square inch per square foot of enclosed area, and § 152.51(E) requires fill to be placed in layers no greater than one foot deep and compacted to 95% of Standard Proctor density. A floodplain development permit is required under § 152.18 before any development starts, and § 152.35 names the Planning Director as Floodplain Administrator.