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

Section 17-43(a) of the Glendale floodplain management chapter requires that residential construction, whether new or a substantial improvement, have its lowest floor, including any basement, elevated to or above the Regulatory Flood Elevation (RFE). Section 17-6 defines Freeboard as an additional one foot of height above the Base Flood Elevation (BFE) used as a safety factor, and defines the RFE itself as an elevation one foot above the BFE, meaning Glendale builds in a full foot of freeboard on top of FEMA's mapped flood elevation.

In a Zone AO, where the FIRM panel doesn't specify a BFE, the required elevation defaults to at least two feet above the highest adjacent grade. In Zone A, where no BFE has been determined, the Floodplain Administrator sets the elevation locally under criteria in Section 17-26(b)(3). In Zones AE and AH, the BFE comes from the Flood Insurance Study or FIRM. Nonresidential construction under Section 17-43(b) can either meet the same elevation standard or be dry-floodproofed watertight with walls substantially impermeable to water and structural components able to resist hydrostatic and hydrodynamic loads.

Whichever path is used, a registered professional engineer, architect, or surveyor must certify compliance to the Floodplain Administrator before the project is signed off. Attached garages built below the RFE must be designed with flood openings that let water automatically enter and exit, per Section 17-43(e).