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Building in a flood zone in Irvine

Irvine's own rules on building in a flood zone, with the code text for every value.

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Each rule below links to the section of the Irvine Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Irvine's code says

Irvine code What Irvine's code adds
Floodplain permit
  • Development permit needed before any construction or development, including structures, fill, material storage or drainage facilities.
    Applies: Before work begins in any special flood hazard area.
    § 5-2-13 · code text
    A development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in Section 5-2-7.
Building in a floodway
  • No new buildings or substantial improvements in floodways before FEMA approves a Letter of Map Revision.
    Applies: Other encroachments need an engineer or architect's certification of no base flood rise; homes are barred in the FP-1 floodway district.
    § 5-2-22 · code text
    Prohibit encroachments, including fill, new construction, substantial improvement, and other new development unless certification by a registered professional engineer or architect is provided, demonstrating that encroachments shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge.
Height of the lowest floor
  • At least 1 foot above FIRM depth number over highest nearby grade, or at least 2 feet if none given.
    Applies: New or substantially improved homes in an AO Zone.
    § 5-2-24 · code text
    In an AO Zone, elevated above the highest adjacent grade to a height equal to or exceeding one foot above the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade if no depth number is specified.
  • The lowest floor must be at least 1 foot above the base flood elevation.
    Applies: New or substantially improved homes in an A Zone; the Floodplain Administrator sets the base flood elevation.
    § 5-2-24 · code text
    In an A Zone, elevated at least one foot above the base flood elevation, as determined by the Floodplain Administrator.
  • The lowest floor must be at least 1 foot above the base flood elevation.
    Applies: New or substantially improved homes in flood zones other than A and AO.
    § 5-2-24 · code text
    In all other zones, elevated at least one foot above the base flood elevation.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

What are the rules for building in an Irvine flood zone?

Irvine's code: Development permit needed before any construction or development, including structures, fill, material storage or drainage facilities. (Before work begins in any special flood hazard area.) (§ 5-2-13); At least 1 foot above FIRM depth number over highest nearby grade, or at least 2 feet if none given. (New or substantially improved homes in an AO Zone.) (§ 5-2-24).

General information, not legal advice.

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Ask GoCodebook how Irvine's building in a flood zone rules apply to your situation and get an answer that cites the section.

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Irvine Municipal Code — full text