Lafayette, IN Environmental Rules: Flood Elevation Requirements (2026)

Section 8.08.310(B) requires the lowest adjacent grade (LAG) of residential, commercial, or industrial buildings located outside a mapped Special Flood Hazard Area or IDNR-designated 100-year floodplain, but still subject to flooding from a stream or open ditch, to sit at least two feet above the 100-year flood elevation. The same two-foot freeboard, measured against the 100-year flood elevation or the emergency overflow weir elevation, whichever is higher, applies to structures near a detention or retention pond outside FEMA or IDNR floodplains. Separately, the floor of any basement or crawl space must sit at least one foot above the normal pool level of an adjacent pond or the two-year flood level of a stream or ditch, and placing a basement below the 100-year flood elevation requires a detailed geotechnical analysis first.

Every building's lowest entry elevation must be built so drainage flows away from the structure, with a maximum yard slope of 3:1 anywhere soil was disturbed during construction. Overflow paths from a 100-year storm must be shown on plans and kept in permanent drainage easements free of fences or landscaping. Enforcement runs through Article VII, with Section 8.08.710 civil infraction fines of $500 for a first offense and $1,000 for a subsequent offense, a stop-work order available under Section 8.08.720, and appeals to the Board of Public Works and Safety within thirty days under Section 8.08.760.