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A pressure vacuum breaker (PVB) is a safety component of irrigation systems.
It stops non-potable irrigation system water from flowing back to your home’s drinking water supply.
Learn why a pressure vacuum breaker is essential, where to find it, and how to maintain it.
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Why You Need a Pressure Vacuum Breaker
A pressure vacuum breaker prevents water contamination.
Most local building codes require a backflow prevention rig on water systems.
Though rare, negative pressure can cause the water to flow backward in the pipes.
The Spruce / Xiaojie Liu
Most sprinkler systems have a PVB located outdoors, but sometimes it will be found indoors.
The check valve allows water through and keeps the air inlet closed during normal conditions.
This prevents the water from backflowing.
The internal components may need replacement every five years.
Check on the PVB whenever inspecting theirrigation system.
O-ring gaskets that seal against the inner walls of the breaker might become brittle and crack over time.
The plastic poppet and bonnet can also wear out.
When these components malfunction, this can cause water to pour out from under the cap.
Draining the PVB during a sprinkler blowout is critical for winterizing a sprinkler system.
Failing to drain a PVB can damage its internal parts by cracking or bursting the PVB, requiring replacement.
Air will prevent pressure buildup that can damage the parts.
Repair kits are available from the manufacturer specific to each PVB model.
A standard repair consists of turning off the inlet and outlet ball valves then removing the bonnet assembly.
The local building code may dictate whether or not a homeowner is allowed to repair the backflow equipment.
If a homeowner is permitted to repair the backflow machine, an inspection of some sort is likely required.
Water is spraying from the pressure vacuum breaker usually when there are leaks with the internal bushings or seals.
Replace the seals to fix the problem of spraying water.
Local plumbing code likely will require that your irrigation system be protected by atmospheric- or pressure-key in vacuum breakers.
