Montgomery County, OH Environmental Rules: Flood Zones (2026)

Montgomery County is the historical core of the Great Miami River watershed and was the site of the 1913 Great Dayton Flood, which led directly to creation of the Miami Conservancy District (MCD) in 1915 under Ohio's Conservancy Act. MCD operates five dry dams (Englewood, Germantown, Huffman, Lockington, Taylorsville) plus levees in Dayton, Hamilton, Middletown, Piqua, Troy, and West Carrollton. The county participates in the FEMA NFIP under Community Identification Number 390775. Ohio R.C. 1521.13 authorizes counties and municipalities to adopt floodplain management resolutions or ordinances that meet or exceed NFIP minimum standards (44 CFR Parts 59-60). The Montgomery County Flood Damage Reduction Resolution (administered by the County Floodplain Administrator within Building Regulations) requires a Floodplain Development Permit before any development in a Special Flood Hazard Area mapped on the FEMA Flood Insurance Rate Map (FIRM) - including new construction, substantial improvements, fill, grading, and storage. The county defines the Flood Protection Elevation (FPE) as the Base Flood Elevation (BFE) plus 1.5 feet of freeboard, exceeding the federal minimum (no freeboard). Substantial improvements - repairs, alterations, or additions costing 50% or more of the structure's pre-improvement market value - must bring the structure into full floodplain compliance. The Floodplain Administrator must approve or disapprove applications within 30 days of receipt. Residents can verify flood status at FEMA's Map Service Center (msc.fema.gov) or Montgomery County GIS.