San Jacinto, CA Environmental Rules: Flood Elevation Requirements (2026)

Section 15.40.150(C) of the San Jacinto Municipal Code sets the elevation rule for every area of special flood hazard in the City of San Jacinto. The base flood is the flood with a one percent chance of being equaled or exceeded in any given year, and the base flood elevation (BFE) is the water surface elevation shown on the flood insurance rate map for Zones AE, AH, A1-30, VE and V1-V30 (§ 15.40.030). For residential construction and substantial improvements, the lowest floor, including basement, must be elevated one foot above the BFE in AE, AH and A1-30 zones. In an AO zone the floor must be elevated above the highest adjacent grade to a height equal to or exceeding the depth number in feet on the FIRM, or at least one foot above the highest adjacent grade if no depth number is specified.

In an unnumbered A zone with no BFE on the FIRM, the floor is still elevated one foot above the base flood elevation, and the floodplain administrator determines that elevation under § 15.40.120(C) by using any base flood data available from a federal or state agency or another source, following the FEMA 265 guide dated July 1995. When the structure is complete, 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.

Nonresidential buildings either meet the same elevation or are floodproofed so the structure is watertight with walls substantially impermeable to water, with components that resist hydrostatic and hydrodynamic loads and buoyancy, backed by a certification from a registered civil engineer or architect. Fully enclosed areas below the lowest floor used only for parking, access or storage need flood openings: nonengineered designs need at least two openings on different sides with a total net area of not less than one square inch for every square foot of enclosed area, and the bottom of every opening no higher than one foot above grade.

Areas below the BFE cannot be finished as living space. Where an enclosed area below the lowest floor is five feet or higher, the applicant signs a nonconversion agreement recorded with the Riverside County recorder as a deed restriction, and the administrator can inspect below the BFE on at least seventy-two (72) hours' notice (§ 15.40.120(J)).