Pismo Beach, CA Environmental Rules: Flood Elevation Requirements (2026)

Section 15.44.050 defines the base flood as a flood with a one percent chance of being equaled or exceeded in any given year, and the base flood elevation as the elevation shown on the Flood Insurance Rate Map for Zones AE, AH and VE for that flood. Under § 15.44.170(C)(1) a new or substantially improved residential structure must have its lowest floor, including basement, elevated to or above that base flood elevation in AE, AH and A zones. In an AO zone the lowest 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 two feet above the highest adjacent grade if no depth number is specified. In an A zone without base flood elevations on the FIRM, the elevation is determined under § 15.44.140(C). When the structure is complete, a registered civil engineer or licensed land surveyor must certify the lowest floor elevation, the community building inspector verifies it, and both go to the floodplain administrator.

Nonresidential structures under § 15.44.170(C)(2) must either meet the residential elevation rule or be floodproofed watertight with walls substantially impermeable to water, have structural components that resist hydrostatic and hydrodynamic loads and buoyancy, and carry a registered civil engineer or architect certification. Fully enclosed areas below the lowest floor used solely for parking, building access or storage need flood openings: 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 subject to flooding, the bottom of each no higher than one foot above grade, or an engineer or architect certification. Small accessory structures of 120 square feet or less for parking of no more than two cars or limited storage can have floors below the base flood elevation if they meet the listed conditions. Below-grade crawl spaces must drain within a period not to exceed seventy-two hours, and crawl space construction is not permitted in V zones. Manufactured homes in Zones A, AH, AO and AE go on a permanent foundation with the lowest floor at or above the base flood elevation (§ 15.44.200).