The Backflow for the Sprinkler Is Leaking

Ball Valves

• There are two ball valves located on most backflow devices. These valves control the flow of water at the inlet and outlet portions of the vacuum breaker. Ball valves can develop cracks due to freezing, or begin to leak at the connection point with the main body. Because ball valves are attached to the main body of the device using standard pipe threads, damaged valves can be replaced using standard parts.

Internal Parts

• There is a series of internal components installed inside every backflow device. These parts consist of a spring, a bonnet and an O-ring. Together, these parts allow water to flow in one direction only. When water freezes inside a backflow device, it can damage or destroy one or more of these parts, causing water to leak or spray from the top of the device. All of the internal parts can be replaced by removing the top of the backflow body, removing the old parts and inserting pieces from a repair kit.

Supply Line Leak

• The copper or plastic supply lines that carry water from the main line to the backflow device are connected to the device using a compression fitting. This fitting can develop leaks when the fitting is not tight. Using an adjustable wrench to tighten the compression nut around the supply line at least once per year will help make sure the line doesn't leak. A leaky supply line will not damage your sprinklers, but it will waste water over time.

Main Body

• The main body of a sprinkler backflow device is usually made of brass. While brass is a very strong material, it can crack when water freezes inside. The pressure from frozen water will press against the sides of the body, creating cracks that will leak. Very minor cracks can be repaired using plumber's epoxy, but cracks larger than 1/4 inch will require you to replace the entire unit with a new one. It's not safe to use a damaged backflow device under any circumstances.