September
2006
BackFlow Preventors Are Your Friend
A backflow preventor valve assembly is a pretty common part of any sprinkler job. If you are watering your lawn with the same water that you drink or use for other purposes you want one of these, and in most cases the law requires it. This valve is to ensure that any chemicals that are on your lawn do not flow back into the common water system from your sprinkler system, so really it’s an elaborate one way valve.
This valve in usually installed as the first part of your sprinkler system and is where all the water that feeds the system will come from. The pictured backflow preventor is called a Pressure Vacuum breaker. It is commonly used so that your valve is visible and accessable above ground. With this type of backflow preventor, you always want to make sure it is installed at least 6″ above the highest sprinkler head in your system so no gravity feed can passively go back into the system.
There are a number of different backflow preventor styles, some of which include the Reduced Pressure, Atmospheric and the Double Check. All of these will usually require yearly inspection by your city or local government.