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

370 requires manufactured homes placed, replaced, or substantially improved on sites in an existing manufactured home park or subdivision to be elevated so that either the lowest floor, or the bottom of the lowest horizontal structural member, is at or above the base flood elevation, or alternatively so the bottom of the frame rests on reinforced piers or equivalent foundation elements at least thirty-six inches high above grade. 380 replaces the state Appendix G rule for detached garages and accessory storage structures used only for parking or storage: they may sit below the base flood elevation only if they are one story, no larger than 600 square feet, anchored against flotation and lateral movement, built with flood openings meeting the building code, constructed of flood damage-resistant materials below the base flood elevation, and have mechanical, plumbing and electrical systems elevated to or above the base flood elevation.

320 sets the trigger at cumulative work costing fifty percent or more of the structure's market value within a rolling ten-year period beginning with the first permitted improvement after January 1, 2023. Once work crosses that threshold, or the structure has suffered substantial flood damage, compliance with the base flood elevation standard is mandatory regardless of the actual repair scope. 120.