Building in a flood zone in Palo Alto: the local rules

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

What Palo Alto's code says

Palo Alto code What Palo Alto's code adds
Floodplain permit	Build in a special flood hazard area only with a development permit; required building, electrical, plumbing or grading permits count. Applies: Construction or development in any special flood hazard area. § 16.52.110 · code text A development permit shall be obtained before construction or development begins within any area of special flood hazard established by Section 16.52.060.
Building in a floodway	Fill, new buildings and other development are not allowed unless a professional engineer certifies no rise in flood levels. Applies: Areas designated as floodways. § 16.52.170 · code text Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless certification by a registered professional engineer is provided demonstrating that encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge.
Height of the lowest floor	Lowest floor at least 2 feet above highest nearby ground or 1 foot above base flood elevation, whichever is higher. Applies: New or substantially improved homes in an A zone. § 16.52.130 · code text In an A zone, shall be elevated at least two feet above the highest adjacent grade if no depth number is specified or one foot above the base flood elevation, whichever is higher; The lowest floor must be at least 1 foot above the base flood elevation. Applies: New or substantially improved homes in all other zones, including Coastal A zones. § 16.52.130 · code text In all other zones, including Coastal A zones shall be elevated at least one foot above the base flood elevation. Basement floors: at or above base flood elevation plus 1 foot, or design flood elevation, whichever is higher. Applies: Basement floors below ground on all sides, in new or substantially improved homes. § 16.52.130 · code text Basement floors that are below grade on all sides shall be elevated to or above base flood elevation plus 1 foot, or design flood elevation, whichever is higher. The lowest floor must be at least the FIRM depth number plus 1 foot above the highest nearby ground. Applies: New or substantially improved homes in an AO zone with a depth number. § 16.52.130 · code text In an AO zone, shall be elevated to a height above the highest adjacent grade of not less than the depth number specified in feet on the Flood Insurance Rate Map plus 1 foot, The lowest floor must be at least 3 feet above the highest nearby ground. Applies: New or substantially improved homes in an AO zone with no depth number. § 16.52.130 · code text or not less than 3 feet above the highest adjacent grade if no depth number is specified;

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Frequently asked questions

What are the rules for building in a Palo Alto flood zone?

Palo Alto's code: Build in a special flood hazard area only with a development permit; required building, electrical, plumbing or grading permits count. (Construction or development in any special flood hazard area.) (§ 16.52.110); Lowest floor at least 2 feet above highest nearby ground or 1 foot above base flood elevation, whichever is higher. (New or substantially improved homes in an A zone.) (§ 16.52.130).

Building in a flood zone in Palo Alto

What Palo Alto's code says

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