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

City Code section 151-04 defines the Regulatory Flood Elevation (RFE) as an elevation one foot above the Base Flood Elevation (BFE), building in a mandatory one-foot freeboard margin above FEMA's mapped flood elevation. Section 151-18(C)(1) carries that standard into construction: residential new construction and substantial improvements must have the lowest floor, including any basement, elevated to or above the RFE. In an AO Zone, that means the elevation shown on the FIRM panel or, if unspecified, at least two feet above the highest adjacent grade; in an A Zone without a determined BFE, the lowest floor must reach the RFE; in AE and AH zones, the BFE comes from the Flood Insurance Study or FIRM.

A garage attached to a residence with its slab below the RFE must be built to allow floodwater to enter and exit automatically and may be used only for parking, access or storage. Nonresidential structures under section 151-18(C)(2) must either meet the same elevation or be floodproofed below it so the structure is watertight, with walls substantially impermeable to water and structural components able to resist hydrostatic and hydrodynamic loads. Upon completion, a registered professional engineer or surveyor must certify the lowest floor elevation, verified by the city's building inspector, and that certification goes to the Floodplain Administrator.

Section 151-17(I)(5)(n) separately bars new construction, fill or other development in Zone AE unless it is shown the cumulative effect will not raise the BFE by more than one foot anywhere in the city.