South Gate, CA Environmental Rules: Flood Elevation Requirements (2026)

Residential construction, new or substantial improvement, shall have the lowest floor, including basement,

i. In an AR (with base flood depth) zone, elevated 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.

ii. In an A zone, elevated to or above the base flood elevation, as determined by this community.

iii. In all other zones, elevated to or above the base flood elevation. Upon completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor, and verified by the community building inspector to be properly elevated. Such certification and verification shall be provided to the floodplain administrator.

b. Nonresidential construction, new or substantial improvement, shall either be elevated to conform with subsection (A)(3)(a) of this section or together with attendant utility and sanitary facilities.

i. Be floodproofed below the elevation recommended under subsection (A)(3)(a) of this section so that the structure is watertight with walls substantially impermeable to the passage of water;

ii. Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and

iii.