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Downey · Building on your lot

Building in a flood zone in Downey

Downey'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 Downey Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Downey's code says

Downey code What Downey's code adds
Floodplain permit
  • A building or grading permit is needed before work begins.
    Applies: For new construction, development or substantial improvement in any area of special flood hazards.
    § 8710.01 · code text
    A building or grading permit shall be obtained before new construction or development or substantial improvement begins within any area of special flood hazards, established in Section 8700.05.
Height of the lowest floor
  • Above the highest adjacent grade, at least as high as the depth number in feet on the FIRM.
    Applies: New homes in the AR zone with a base flood depth.
    § 8710.06 · code text
    In the AR (with base flood depth) zone, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM, or at least two feet (2') if no depth number is specified.
  • At least 2 feet above the highest adjacent grade.
    Applies: New homes in the AR zone with a base flood depth, when the FIRM gives no depth number.
    § 8710.06 · code text
    In the AR (with base flood depth) zone, elevated above the highest adjacent grade at least as high as the depth number specified in feet on the FIRM, or at least two feet (2') if no depth number is specified.
  • The lower of the AR base flood elevation or 3 feet above the highest adjacent grade.
    Applies: New homes in the AR zone.
    § 8710.06 · code text
    In the AR zone, elevated using the lower of either the AR base flood elevation or the elevation that is three feet above the highest adjacent grade.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

What are the rules for building in a Downey flood zone?

Downey's code: A building or grading permit is needed before work begins. (For new construction, development or substantial improvement in any area of special flood hazards.) (§ 8710.01); Above the highest adjacent grade, at least as high as the depth number in feet on the FIRM. (New homes in the AR zone with a base flood depth.) (§ 8710.06).

General information, not legal advice.

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

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Downey Municipal Code — full text