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

070(D) sets Petaluma's freeboard standard: new construction and substantial improvement or substantial-damage repair of any residential structure in the FP-C (Flood Plain-Combining) zone must have its lowest habitable floor, including any basement, elevated at least 12 inches above the base flood elevation or the depth number shown on the Flood Insurance Rate Map (FIRM), whichever applies. That 12-inch freeboard also covers all mechanical, electrical, heating, ventilation, plumbing and air-conditioning equipment, which must sit above the same line. 080(C). 070(D)(1), measured to the lowest floor of each home on reinforced piers or an equivalent foundation, and any new manufactured home park, or an existing park expanding 10 percent or more, must include a written emergency evacuation plan.

070(D)(2), finished floor clearance above the 100-year base flood elevation must be a minimum of two feet, not 12 inches, and any fill placed on a project site there must be offset by removing an equivalent amount of material elsewhere on the parcel or nearby, to the satisfaction of the City Engineer and the Sonoma County Water Agency. 070(E), or may instead be engineered watertight and floodproofed below the base flood level, certified by a registered engineer or architect.