A backflow assembly prevents the reversal of flow due to backpressure and backsiphonage. Backflow assemblies are required to be tested after being installed, after repairs and annually.
A sprinkler system is subsurface and can draw in pollutants/contaminates such as fertilizers and animal wastes through the sprinkler heads. Without a backflow preventer and during a backpressure or backsiphonage situation these pollutants/contaminants could be drawn back into the drinking water.
Backflow assemblies just like anything else can fail over time. This is one of the reasons for the annual testing by a certified Backflow Assembly Tester. We have two certified Backflow Assembly Testers.