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

Section C4-67 of the Flood Insurance Program chapter sets San Ramon's construction elevation standard. Subsection A requires new construction and substantial improvement of any structure to have the lowest floor, including any basement, elevated to or above the base flood elevation (BFE), the level of the flood with a one percent annual chance of occurring, defined in Section C4-49. That elevation must be certified by a registered professional engineer or surveyor, or verified by the city building inspector, and the certification filed with the floodplain administrator in FEMA's approved format.

Subsection B adds a freeboard-style buffer for Zones AE, AH, A1-30, and AO: the lowest floor must sit above the BFE, or at least two feet above grade if the FIRM specifies no depth number for that zone. Nonresidential buildings may instead dry-floodproof under Subsection C, making the structure watertight below the BFE, resisting hydrostatic and hydrodynamic loads, and carrying an engineer's or architect's certification. Subsection D lets an attached garage or a small detached garage or shed (under 150 square feet and $1,500 in value, per Section C4-49) sit below the BFE only if built with flood-resistant materials, anchored against flotation, and equipped with automatic flood-water entry openings; larger accessory structures must meet the full Article 3 standards.

Subsection E requires enclosed areas below the lowest floor to equalize hydrostatic pressure, either by professional engineering certification or by at least two openings totaling one square inch of net area per square foot of enclosed area, with opening bottoms no higher than one foot above grade. Manufactured homes must also satisfy Section C4-70. Compliance is verified through the Section C4-61 development permit process before construction begins.