XERISCAPE: LANDSCAPING WITH STYLE in the ARIZONA DESERT

       


Install Backflow Prevention Assembly
Backflow prevention assemblies are required for all irrigation systems regardless of size. The purpose of these devices is to prevent contaminated water from getting into the drinking water system. If you need to install a backflow preventer, it is necessary to obtain a plumbing permit and follow all city code requirements. If you haven't done so already, call your city for permit information. To ensure proper installation that will pass a city inspection, it is recommended that you hire a contractor to install this irrigation system component. Here are some guidelines that your contractor should follow during the installation process:
  • Backflow preventer assemblies are typically installed near the water source at least twelve inches from a wall to allow for access. There are many types of backflow preventers available. The Uniform Plumbing Code (UPC) has specific installation requirements depending on type.
  • Pressure vacuum breakers (PVBs) or reduced pressure assemblies (RPs) are recommended since one assembly can serve multiple valves. Although atmospheric vacuum breakers (AVBs) are easier to install, they cannot be tested to see if they are functioning properly. In addition, an AVB is required for every control valve.

Illustration Backflow Preventer
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  • Type K copper pipe should be used for all above ground piping and requires a torch and non-lead solder ("sweat") to connect the copper fittings.
  • A ball valve should be installed on the riser going to the backflow preventer to shut off the water during emergencies or repairs.
  • At least one union should be installed within one foot of the backflow prevention assembly for ease of repair or replacement.
  • With a PVB or RP, the irrigation valves must be installed after the assembly. However, the AVB must have the valve installed before the assembly.
  • If your home already has a front yard landscape with a backflow preventer, it is fairly easy to extend additional valves from the front yard to the back yard. If you extend the existing system, follow the rules specified in the Uniform Plumbing Code.

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Illustration Backflow Preventer General Placement of Landscape Irrigation Components Standard Installation Detail for Valve Boxes, Valves, Filters, and Pressure Regulators

 
 
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