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

Highland Municipal Code § 16.76.050 sets the flood hazard reduction standards for every area of special flood hazard in the City of Highland. For residential structures, new construction and substantial improvements must have the lowest floor, including basement, elevated one foot above the base flood elevation in AE and A1–A30 Zones. In an A Zone without base flood elevations specified on the FIRM, the unnumbered A Zone, the lowest floor must be elevated two feet above the base flood elevation, as determined under § 16.76.040(B)(3). 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 structures either meet the same elevation standard or are floodproofed so the structure is watertight with walls substantially impermeable to water and has structural components able to resist hydrostatic and hydrodynamic loads. A registered civil engineer or architect certifies the floodproofing to the floodplain administrator.

Fully enclosed areas below the lowest floor that are used solely for parking, building access or storage need flood openings. Non-engineered openings need a minimum of 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. Otherwise a registered civil engineer or architect certifies the design. Detached garages of two cars or smaller and small, low-cost sheds can sit below the base flood elevation if used only for parking or limited storage, built with flood-resistant materials, anchored, and designed for automatic entry of floodwaters. Below-grade crawl spaces cannot be more than two feet below the lowest adjacent exterior grade, cannot exceed four feet in height, and must drain within 72 hours.

A development permit is required before any construction or other development in an area of special flood hazard, with plans showing the proposed elevation of the lowest floor in relation to mean sea level. Where an enclosed area below the lowest floor is five feet or higher, the floodplain administrator requires a non-conversion agreement recorded with the San Bernardino county recorder as a deed restriction, and can inspect below the base flood elevation on at least 72 hours notice. The City Council of the City of Highland hears appeals from floodplain administrator decisions.