Building in a flood zone in Lake Forest: the local rules

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

What Lake Forest's code says

Lake Forest code What Lake Forest's code adds
Floodplain permit	A development permit is needed before construction or development begins; plans may show structures, fill, storage, drainage and elevations. Applies: In any area of special flood hazards. § 8.70.210 · code text A development permit shall be obtained before construction or development begins within any area of special flood hazards established in Section 8.70.115.
Building in a floodway	No fill, new construction, substantial improvements or other development unless analyses show no flood level increase. Applies: In designated floodways; hydrologic and hydraulic analyses must cover the base flood discharge; other flood rules still apply. § 8.70.330 · code text Prohibit encroachments, including fill, new construction, substantial improvements, and other development unless it has been demonstrated through hydrologic and hydraulic analyses performed in accordance with standard engineering practice that the proposed encroachments shall not result in any increase in flood levels during the occurrence of the base flood discharge;
Height of the lowest floor	At least as high as the FIRM depth number, and at least 1 foot above the highest adjacent grade. Applies: New or substantially improved buildings, including homes, in an AO zone with a depth number on the FIRM. § 8.70.310 · code text In an AO zone, new construction for residential and nonresidential and substantial improvement of a structure shall be elevated at least one foot above the highest adjacent grade to a height equal to or exceeding 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. At least 2 feet above the highest adjacent grade. Applies: New or substantially improved buildings, including homes, in an AO zone with no depth number on the FIRM. § 8.70.310 · code text In an AO zone, new construction for residential and nonresidential and substantial improvement of a structure shall be elevated at least one foot above the highest adjacent grade to a height equal to or exceeding 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. At least 1 foot above the base flood elevation. Applies: New or substantially improved buildings, including homes, in all other special flood hazard zones, including zone A. § 8.70.310 · code text In all other SFHA zones, including zone A, new construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to at least one foot above the base flood elevation.

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Frequently asked questions

What are the rules for building in a Lake Forest flood zone?

Lake Forest's code: A development permit is needed before construction or development begins; plans may show structures, fill, storage, drainage and elevations. (In any area of special flood hazards.) (§ 8.70.210); At least as high as the FIRM depth number, and at least 1 foot above the highest adjacent grade. (New or substantially improved buildings, including homes, in an AO zone with a depth number on the FIRM.) (§ 8.70.310).

Building in a flood zone in Lake Forest

What Lake Forest's code says

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