Placer County, CA Environmental Rules: Flood Elevation Requirements (2026)

52, the Flood Damage Prevention ordinance, governs building in the 100-year floodplain shown on FEMA's Flood Insurance Rate Maps. 170(C)(1) requires that new construction and substantial improvements have the lowest floor, including basement, elevated a minimum of one foot above the base flood elevation (BFE), and it recommends a two-foot freeboard so floor joists, insulation and other components under the finish floor are not inundated. In an AO zone with no depth number specified, the lowest floor must sit at least three feet above the highest adjacent grade.

170(C)(2). Before any framing begins above the lowest floor, a registered civil engineer or licensed land surveyor must certify the elevation on the county's elevation certificate, filed with the floodplain administrator through the public works department. 170(B)(3). 200. Enclosed areas below the lowest floor used only for parking, access or storage must have flood vents equalizing hydrostatic pressure: at least two openings totaling one square inch of net area per square foot of enclosed space, with opening bottoms no higher than one foot above grade. Freeboard requirements do not apply to the Tahoe Basin's TRPA-permitted development, which follows the bi-state agency's own standards rather than this county article.