Pico Rivera, CA Environmental Rules: Flood Elevation Requirements (2026)

Pico Rivera Municipal Code § 15.50.525(C)(1) sets the city's elevation standard for construction inside its mapped flood hazard areas along the Rio Hondo and San Gabriel Rivers. For residential construction in an AR zone, the lowest floor, including any basement, must be elevated above the highest adjacent grade to a height equal to the lower of either the AR base flood elevation or the elevation that is three feet above the highest adjacent grade, but in no event less than two feet above the highest adjacent grade.

Once built, that elevation has to be proven: the same subsection requires the lowest-floor elevation to be certified by a registered professional engineer or surveyor and verified by the city's building inspector before the floodplain administrator, who under § 15.50.500 is the director of public works, signs off. Nonresidential buildings get an alternative under subsection (C)(2): instead of elevating, they may be floodproofed watertight below the same reference elevation, provided a licensed engineer or architect certifies the design resists hydrostatic and hydrodynamic loads. Section 15.50.525 also requires enclosed areas below the lowest floor used only for parking, access, or storage to have flood-vent openings totaling at least one square inch per square foot of enclosed area, with the lowest opening no higher than one foot above grade, so floodwater can enter and exit without pushing against the walls.

These elevation and floodproofing rules apply on top of, not instead of, the federal Flood Insurance Rate Map data that § 15.50.420 adopts as the basis for identifying which parcels are in a special flood hazard area.