Lodi, CA Environmental Rules: Flood Elevation Requirements (2026)

180(C) sets Lodi's construction standards for the special flood hazard area. Residential structures in Zones AE, AH, and A1-30 must have their lowest floor, including any basement, elevated to eighteen inches or more above the base flood elevation; an AO Zone instead uses the FIRM's depth number above the highest adjacent grade, or two feet if no depth number is shown. Structures inside the city's -F200 overlay, covering the mapped 200-year floodplain along the Mokelumne River, must have their finished floor at or above the elevation of the 200-year flood, a higher local standard the city added on top of the federal 100-year requirement.

A registered civil engineer or licensed land surveyor must certify the as-built lowest-floor elevation, and the city's building inspector verifies it before the certification goes to the floodplain administrator. Nonresidential buildings may instead be dry-floodproofed below the required elevation if an engineer or architect certifies the walls are substantially impermeable and can resist hydrostatic and hydrodynamic loads. 180(C)(3).