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

071(B) requires new construction or substantial improvement of any residential structure or manufactured home in the SFHA to have its lowest floor, including basement, built at or above that FPG. 071(C) must either be elevated to the FPG or fully floodproofed to that level, with the floodproofing design certified watertight by a registered professional engineer or architect and capable of resisting hydrostatic and hydrodynamic flood forces without human intervention or outside electricity. 071(A): new construction over 400 square feet, an addition or improvement costing 50% or more of the structure's value, repair of damage costing 50% or more of pre-damage market value, installing a manufactured home or a travel trailer or RV on site more than 180 days, or repair of a repetitive-loss structure.

071(D): at least two openings in two different exterior walls sized to one square inch of net opening per square foot of enclosed area, with the bottom of each opening no more than one foot above grade, and the enclosed space below the FPG left unfinished and unpartitioned. 071(E) must be compacted to 95% of maximum density, extend at least ten feet beyond the foundation before sloping below the base flood elevation, and be protected against erosion. 051(B) and (C).