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

Section 15.24.160 applies in all special flood hazard areas. Subsection C.1 covers residential construction, meaning all new construction and substantial improvements, and sets the height of the lowest floor, including any basement. In AE, AH, and A1-30 zones it is elevated to or above the base flood elevation. In an AO zone it is elevated above the highest adjacent grade to a height equal to or exceeding the depth number in feet on the FIRM, or at least two feet above the highest adjacent grade if no depth number is specified. In an unnumbered A zone the floor is elevated to or above a base flood elevation determined under Section 15.24.130.C. The subsection sets the floor at the base flood elevation itself and prints no separate freeboard figure.

When the structure is finished, a registered civil engineer or licensed land surveyor certifies the lowest floor elevation, the community building inspector verifies it, and the certification goes to the Floodplain Administrator. Section 15.24.050 defines the base flood elevation as the water surface elevation of a flood with a one percent or greater chance of occurring in any year, shown on the FIRM for Zones AE, AH, A1-30, VE, and V1-V30.

Nonresidential buildings are elevated the same way or floodproofed watertight with an engineer or architect certification (§ 15.24.160.C.2). Enclosures below the lowest floor used only for parking, access, or storage need at least two openings on different sides totaling one square inch of net area per square foot of enclosed area, with bottoms no higher than one foot above grade. Residential subgrade enclosed areas are prohibited because they count as basements. Manufactured homes follow Section 15.24.190, and detached garages of two cars or fewer can sit below the base flood elevation if six listed conditions are met (§ 15.24.160.C.5).