Yes. For any backflow prevention assembly containing a relief port, the code requires that “the relief opening shall discharge by air gap and shall be prevented from being submerged.” Manufacturer installation instructions typically suggest installing the backflow device 12-30 inches above outside grade, with a minimum of 12 inches above surrounding flood level. Typical engineering construction standards show a minimum of 12 inches from the relief port to outside grade.
In designated flood hazard areas as defined by the code, Section 1612 of the FBC-Building requires design flood elevations to be established or determined. The backflow preventer should then be installed so that the relief port is a minimum of 12 inches above the design flood elevation.
