Peoria, AZ Environmental Rules: Flood Elevation Requirements (2026)

Sec. 20-205 defines "Base flood" as the flood with a one percent annual chance of occurring, also called the 100-year flood, and "Base flood elevation (BFE)" as the computed elevation floodwater is anticipated to reach during that event. The same section then defines "Regulatory Flood Elevation (RFE)" as one foot above the base flood elevation, building a one-foot freeboard margin into every elevation standard that follows. Sec. 1 applies that margin: new or substantially improved residential construction in Zones AE, AH and A1-30 must have its lowest floor, including any basement, built to or above the Regulatory Flood Elevation, with the finished elevation certified by a registered professional engineer or surveyor and verified by the city building inspector before it goes to the Floodplain Administrator.

In an AO Zone, the standard is elevation to the regulatory flood depth or two feet above the highest adjacent grade if no depth number is mapped. Sec. 2 gives nonresidential buildings an alternative: floodproof below the Regulatory Flood Elevation instead of elevating, with watertight, substantially impermeable walls and structural components able to resist hydrostatic and hydrodynamic loads, certified by a registered engineer or architect. Sec. 3 further requires enclosed areas below the lowest floor used only for parking, storage or building access to include flood openings that automatically equalize hydrostatic pressure during flooding.