Phoenix, AZ Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard
- 1 ft above BFE (RFE)
- Zone AO minimum
- 2 ft above adjacent grade
- Applies to
- Lowest floor, incl. basement
- Enforced by
- City Engineer / Floodplain Administrator
- Proof required
- PE or surveyor elevation certificate
Summary
New homes in Phoenix flood zones must sit at least one foot above the base flood elevation, the city's built-in freeboard margin.
Regulatory flood elevation (RFE) means an elevation one foot above the base flood elevation for a watercourse. ... Residential construction, new or substantial improvement, must have the lowest floor, including basement, elevated to or above the regulatory flood elevation.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance G-7524, passed June 17, 2026).
Full Breakdown
Phoenix defines the Regulatory Flood Elevation as one foot above the FEMA base flood elevation, and City Code § 32B-20(C)(1) requires new or substantially improved residential construction to have its lowest floor, including any basement, elevated to or above that regulatory flood elevation. In Zone AO, if no BFE is specified, the minimum is two feet above the highest adjacent grade. Nonresidential structures may floodproof instead of elevate. A registered engineer or surveyor must certify the final elevation to the Floodplain Administrator before the structure is signed off.
Violations & Fines
Building below the required elevation without engineer certification is a code violation; the Floodplain Administrator can withhold final approval and the property is presumed in violation until proof of compliance is filed.
Frequently Asked Questions
What is Phoenix's Regulatory Flood Elevation?
Do I need certification after building?
Sources & Official References
Other rules in Phoenix
Compare Phoenix to another location·View the Arizona environmental rules overview
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Flood Elevation Requirements in Nearby Cities
How other cities in Maricopa County handle flood elevation requirements.