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

Eastvale Municipal Code § 110.80.170(3)(a) requires that residential structures undergoing new construction or substantial improvement "shall have the lowest floor, including basement...In AE, AH, A1-A30 zones, elevated to or above the base flood elevation," with AO zones instead requiring elevation to the depth number shown on the FIRM or, absent a specified depth, at least two feet above the highest adjacent grade. Once construction is finished, "the elevation of the lowest floor, including basement, shall be certified by a registered civil engineer or licensed land surveyor, and verified by the community building inspector," with that certification filed with the floodplain administrator, a role assigned to the city manager under § 110.80.130.

Nonresidential buildings have an alternative under § 110.80.170(3)(b): instead of elevating, they may be dry-floodproofed so the structure is watertight and can resist hydrostatic and hydrodynamic loads, again certified by a registered civil engineer or architect. Detached garages and small accessory structures get their own carve-out in § 110.80.170(3)(e): a two-car garage or small storage shed may have its floor below the base flood elevation if limited to parking or storage, built with flood-resistant materials below the BFE, anchored against flotation, and designed to let floodwater automatically enter and exit under the opening standards in § 110.80.170(3)(c). The base flood elevation itself is defined at § 110.80.050 as the water surface elevation of the flood having a one-percent annual chance of occurring, drawn from FEMA's Flood Insurance Rate Maps for the applicable zone.