Prescott Valley, AZ Environmental Rules: Flood Elevation Requirements (2026)

Town Code § 12-05-010 sets the construction standards that apply in every Special Flood Hazard Area in the Town of Prescott Valley. For residential construction, new or a Substantial Improvement, subsection (C)(1) requires the Lowest Floor, including any Basement, to sit at or above the RFE. The Article 12-02 definitions fix the RFE at an elevation 1 foot above the Base Flood Elevation. How the BFE is found depends on the flood zone. In Zones AE and AH it comes from the Flood Insurance Study and the FIRM. In Zone AO it comes from the FIRM panel, and if the panel is silent the required elevation is at minimum two feet above the Highest Adjacent Grade. In Zone A where no BFE has been determined, the Town sets it locally under § 12-04-020(C).

A garage attached to a house may have its slab below the RFE only if it is designed to let floodwaters enter and exit automatically and is used solely for parking access and storage. When the structure is finished, a civil engineer registered in Arizona must certify the elevation of the lowest floor to the Floodplain Administrator.

Commercial and industrial buildings have a second route. Under subsection (C)(2) the lowest floor can be elevated, or the building, with its utility and sanitary facilities, can be floodproofed so it is watertight with walls substantially impermeable to water and structural components able to resist hydrostatic and hydrodynamic loads and buoyancy. An engineer or architect registered in Arizona certifies the floodproofing.

Detached garages and storage structures under subsection (C)(4) can have a floor below the RFE if they are limited to parking or storage, built with flood resistant materials below the RFE, anchored, and have machinery elevated or floodproofed to or above the RFE. Fully enclosed areas below the lowest floor need flood openings under subsection (C)(5): at least two openings on different sides, one square inch of net area for every square foot of enclosed area, with the bottom of every opening no higher than one foot above grade.

Relief comes only through the Town Council acting as Floodplain Board under Article 12-06. Section 12-06-030 allows a variance on a lot of one-half acre or less surrounded by lots with structures built below the RFE, and forbids any variance in a Floodway if flood levels would rise.