Atmospheric Vacuum Breaker (AVB): AVB’s must be installed at least 6 inches above the highest sprinkler that it serves but not higher than 5 feet above the ground. Control valves are not allowed downstream from the AVB. The AVB shall not be pressurized for more than 12 hours in any 24 hour period. If you have six sets on your sprinkler system you must have six control valves installed in front of six AVB’s. The AVB’s must be installed with adequate room for inspecting and maintenance.
Double Check Valve Assembly (DCVA): DCVA’s can be installed below ground in a vault or above ground not higher than 5 feet above ground. Control valves are allowed anywhere in the piping system. The DCVA must be installed with adequate room for testing and maintenance. If the DCVA is installed below ground sufficient drainage must be provided to prevent the assembly from being submerged. The DCVA is the most common backflow assembly used for sprinkler systems in the Yakima Valley.
Pressure Vacuum Breaker Assembly (PVBA): PVBA’s must be installed at least 12 inches above the highest sprinkler that it serves but not higher than 5 feet above the ground. Control valves are allowed anywhere in the piping system. The PVBA must be installed with adequate room for testing and maintenance.
Reduced Pressure Backflow Assembly (RPBA): RPBA’s are required on sprinkler systems if the system is connected to the drinking water and also any auxiliary water such as private wells or irrigation districts. RPBA’s must be installed above ground level and inspected before use by Yakima County. Irrigation water generally comes from open ditches and rivers. Contamination such as E.coli, Giardia, Cryptosporidium cyst, and other Bacteria can enter the drinking water system from auxiliary water if it is not properly protected with an RPBA.