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

Chapter 9.80's construction standards apply throughout Roseville's mapped areas of special flood hazard. Under §9.80.160(C)(1), any new residential structure, or a substantial improvement to an existing one, must have its lowest floor, including a basement, elevated at least two feet above the base flood elevation (BFE) supplied by the floodplain administrator, the community development director. The two-foot freeboard covers not just the living space but every piece of the structure's support equipment, including electrical, heating, ventilation ductwork, plumbing and air conditioning components, that could be damaged if submerged.

Nonresidential new construction or substantial improvement must meet the same elevation standard under §9.80.160(C)(2), or be floodproofed to an equivalent level. Once the building is finished, a registered professional engineer or licensed land surveyor must certify the elevation of the lowest floor and support equipment, and the floodplain administrator must verify the certification before the structure is considered compliant (§9.80.160(C)(1)).

Because owners sometimes build usable space below the required elevation, the city also records a deed restriction limiting any part of the structure below the BFE to parking, building access, or storage, as the public works director determines appropriate. Fully enclosed areas below the lowest floor that are used for parking, access or storage must be engineered to automatically equalize hydrostatic flood pressure, typically through a minimum of two flood vents providing at least one square inch of net opening per square foot of enclosed area, with the lowest opening no higher than one foot above grade (§9.80.160(C)(3)). Roseville has also opted not to adopt California Building Code §1612.3 in place of this local chapter (§9.80.160(D)).