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Mendocino County · Building on your lot

Building in a flood zone in Mendocino County

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

What Mendocino County's code says

Mendocino County code What Mendocino County's code adds
Floodplain permit
  • You need a development permit before any construction or other development begins.
    Applies: Applies within any special flood hazard area.
    § 22.17.305 · 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 22.17.210.
Building in a floodway
  • No fill, construction or other development unless analysis shows no rise in base flood levels.
    Applies: Applies within the adopted regulatory floodway.
    § 22.17.305 · code text
    Unless otherwise demonstrated through the submission of additional engineering data as noted in subsection (G)(1) above, no encroachments, including fill, new construction, substantial improvements, and other development within the adopted regulatory floodway unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that proposed encroachment would not result in any increase in flood levels within the community during occurrence of the base flood dis
Height of the lowest floor
  • Lowest floor: at least flood map depth number plus 1 foot above highest adjacent ground, or 3 feet if none.
    Applies: New or substantially improved homes in an AO zone.
    § 22.17.405 · code text
    In an AO zone, elevated to a height above the highest adjacent grade of not less than the depth number specified in feet (mm) on the FIRM plus one (1) foot (305mm), or not less than three (3) feet (915 mm) if a depth number is not specified.
  • The lowest floor must be at least 1 foot above the base flood elevation.
    Applies: New or substantially improved homes in all flood zones except AO.
    § 22.17.405 · code text
    In all other Zones, elevated at least one (1) foot above the base flood elevation, as determined by the County.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

What are the rules for building in a Mendocino County flood zone?

Mendocino County's code: You need a development permit before any construction or other development begins. (Applies within any special flood hazard area.) (§ 22.17.305); Lowest floor: at least flood map depth number plus 1 foot above highest adjacent ground, or 3 feet if none. (New or substantially improved homes in an AO zone.) (§ 22.17.405).

General information, not legal advice.

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

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