(A) Approved backflow-prevention assemblies.
(1) Only backflow-prevention assemblies which have been approved by the University of Southern California Foundation for Cross-Connection Control and Hydraulic Research are acceptable for installation by a water user connected to the city's potable water system.
(2) The city will provide, upon request, a list of approved backflow-prevention assemblies.
(B) Backflow-prevention assembly installation.
(1) Backflow-prevention assemblies shall be installed in a manner prescribed in § 7603, Title 22 of the State Administrative Code. Location of the assemblies should be as close as practical to the user's connection. The Director of Public Works shall have the final authority in determining the required location of a backflow-prevention assembly.
(a) Air-gap separation (AG). The air-gap separation shall be located on the user's side of, and as close to, the service connection as is practical. All piping from the service connection to the receiving tank shall be above grade and be entirely visible. No water use shall be provided from any point between the service connection and the air-gap separation. The water inlet piping shall terminate a distance of at least two pipe diameters of the supply inlet, but in no case less than one-inch above the overflow rim of the receiving tank.
(b) Reduced pressure principle backflow-prevention assembly (RP). The approved reduced pressure principle backflow-prevention assembly shall be installed on the user's side of, and as close to, the service connection as is practical. The assembly shall be installed a minimum of 12 inches above grade and not more than 36 inches above grade measured from the bottom of the assembly and with a minimum of 12 inches side clearance. The assembly shall be installed so that it is readily accessible for maintenance and testing. Water supplied from any point between the service connection and the RP assembly shall be protected in a manner approved by the Director of Public Works.
(c) Double check-valve assembly (DC). The approved double check-valve assembly shall be located as close as practical to the user's connection and shall be installed above grade, if possible, and in a manner where it is readily accessible for testing and maintenance. If a double check-valve assembly is put below grade it must be installed in a vault such that there is a minimum of six inches between the bottom of the vault and the bottom of the assembly, so that the top of the assembly is no more than a maximum of eight inches below grade, so there is a minimum of 24 inches of clearance between the side of the assembly with the test cocks and the side of the vault, and so there is a minimum of 12 inches clearance between the other side of the assembly and the side of the vault. Special consideration must be given to double check-valve assemblies of the "Y" type. These assemblies must be installed on their "side" with the tests cocks in a vertical position so that either check valve may be removed for services without removing the assembly. Vaults which do not have an integrated bottom must be placed on a three-inch bottom layer of ¾-inch gravel. Vaults with integrated bottoms must have adequate drain holes and be placed on a three-inch layer of ¾-inch gravel.
(C) Backflow-prevention assembly testing and maintenance.
(1) The owners of any premises on which, or on account of which, backflow-prevention assemblies are installed, shall have their assemblies tested by a person who is certified and licensed by the state to test backflow assemblies. Backflow-prevention assemblies must be tested at least annually and immediately after installation, relocation, or repair. The Director of Public Works may require a more frequent testing schedule if it is determined to be necessary. No assembly shall be placed back in service unless it has been certified as functioning properly. A report in a form acceptable to the city shall be filed with the Director of Public Works each time an assembly is tested, relocated, or repaired. These assemblies shall be serviced, overhauled, or replaced whenever they are found to be defective and all costs of testing, repair, and maintenance shall be borne by the water user.
(2) The city will supply affected water users with a list of persons acceptable to the city to test backflow-prevention assemblies. The city will notify affected customers by mail when annual testing of an assembly is required. Necessary forms shall be provided and filled out by the certified tester each time an assembly is tested or repaired.
(D) Backflow-prevention assembly removal.
(1) Approval must be obtained from the Director of Public Works before a backflow- prevention assembly is removed, relocated, or replaced.
(a) Removal. The use of an assembly may be discontinued and the assembly removed from service upon presentation of sufficient evidence to the Director of Public Works to verify that a hazard no longer exists or is not likely to be created in the future. The assembly may only be removed upon receipt of written permission from the Director of Public Works.
(b) Relocation. An assembly may be relocated following written confirmation by the Director of Public Works that the relocation will continue to provide the required protection and satisfy installation requirements. A retest will be required following the relocation of the assembly.
(c) Repair. An assembly may be removed for repair, provided the water use is either discontinued until repair is completed and the assembly is returned to service, or the service connection is equipped with other approved and tested backflow protection. A retest will be required following the repair of the assembly.
(d) Replacement. A water assembly may be removed and replaced provided the water use is discontinued until the replacement assembly is installed, tested, and certified. All replacement assemblies must be approved by the city and must be commensurate with the degree of hazard involved.