Backflow prevention devices shall be installed in a manner prescribed in Section 7603, Title 22 of the California Administrative Code. Location of the devices should be as close as practicable to the user’s connection. The city shall have the final authority in determining the required location of a backflow prevention device.
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 from 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 Device (RP). The approved reduced pressure principle backflow prevention device shall be installed on the user’s side of and as close to the service connection as is practical. The device shall be installed a minimum of twelve inches above grade and not more than thirty-six inches above grade measured from the bottom of the device and with a minimum of twelve inches side clearance. The device 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 device shall be protected in a manner approved by the city.
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 device, so that the top of the device is no more than a maximum of eight inches below grade, so there is a minimum of six inches of clearance between the side of the device with the test cocks and the side of the vault, and so there is a minimum of three inches clearance between the other side of the device and the side of the valve. Special consideration must be given to double check valve assemblies of the "Y" type. These devices must be installed on their side with the test cocks in a vertical position so that either check valve may be removed for service without removing the device. Vaults which do not have an integrated bottom must be placed on a three-inch layer of gravel.
(Ord. 88-01 § 4(B), 1988)