A. Approval: Only approved backflow prevention devices shall be acceptable for installation by a water user. Upon request, the city will provide a list of approved backflow prevention devices to any affected user.
B. Installation: Backflow prevention devices shall be installed in a manner prescribed by section 7603 of title 17 of the California Code of Regulations. Location of the devices should be as close as practical to the user's service connection. However, the city shall have the authority to determine the required location of a backflow prevention device. Installation shall also be consistent with the following requirements:
1. Air Gap Separation (AG): An air gap separation shall be located on the user's side of the service connection 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 at a distance of at least two (2) pipe diameters of the supply inlet, but in no case less than one inch (1"), above the overflow rim of the receiving tank.
2. Reduced Pressure Principle Backflow Prevention Device (RP): The approved reduced pressure principle backflow prevention device shall be installed on the user's side of the service connection and as close to the service connection as is practical. The device shall be installed a minimum of twelve inches (12") above grade and not more than thirty six inches (36") above grade measured from the bottom of the device and with a minimum of twelve inches (12") 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.
3. Double Check Valve Assembly (DC): The approved double check valve assembly shall be located as close as practical to the user's service connection and shall be installed above grade, if practicable, and in a manner where it is readily accessible for testing and maintenance. If a double check valve assembly is installed below grade, it must be installed in a vault so that there is a minimum of twelve inches (12") 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 (8") below grade, so that there is a minimum of twenty four inches (24") of clearance between the side of the device with the test cocks and the side of the vault, and so that there is a minimum of twelve inches (12") clearance between the other side of the device and the side of the vault. Vaults which do not have an integrated bottom must be placed on a three inch (3") layer of gravel.
Double check valve assemblies of the "Y" type must be installed on their "side" with tests cocks in a vertical position so that either check valve may be removed for service without removing the device. (1988 Code)