Vanderburgh County, IN Environmental Rules: Flood Zones (2026)

Vanderburgh County is an NFIP-participating community. The effective FEMA Flood Insurance Rate Map (FIRM) for Vanderburgh County and Incorporated Areas was issued March 17, 2011 and delineates Special Flood Hazard Areas (SFHAs) including Zone A, AE, AH, AO, and floodway. The Ohio River along the southern county boundary and Pigeon Creek through Evansville are the principal flood sources. Local rules are codified at Vanderburgh County Code Chapter 18.04 (Flood Hazard Protection); the City of Evansville maintains parallel floodplain rules. The Building Commissioner is designated Floodplain Administrator. A Floodplain Development Permit is required for any development - new construction, additions, substantial improvements, fill, grading, mining, drilling, paving, or storage of equipment - within an SFHA before a building permit can be issued. Indiana's standard, reflected in the Vanderburgh ordinance, sets the Flood Protection Grade (FPG) at the Base Flood Elevation plus 2 feet, which is more protective than the federal NFIP minimum. The lowest floor of any new or substantially improved structure must be elevated to or above the FPG; non-residential structures may alternatively be dry-floodproofed to the FPG. Substantial improvement applies when the cost of repair, reconstruction, or improvement equals or exceeds 50% of the structure's pre-improvement market value, triggering full ordinance compliance. After construction, a FEMA Elevation Certificate (Form 81-31) documenting as-built lowest floor elevation must be submitted. State authority is IC 14-28 (Flood Control Act), administered by the Indiana Department of Natural Resources Division of Water; federal authority is the NFIP at 44 CFR Parts 59-60.