Cold Weather Damage to Sprinkler Systems

Damage to Pipes

• Most residential sprinkler pipes are about 1/2 inches in diameter, which is a relatively small pipe that does not have extra room for water to sit in. When the temperature underground dips below the freezing point, water begins to freeze along the pipe. The expansion can burst the pipe or lead to cracks that will leak and eventually break. To identify a broken pipe, turn on your sprinklers and let them run for 20 minutes. Water will begin to pool above ground where the break is located.

Damage to Vacuum Breakers

• The pressure vacuum breaker is a brass valve assembly that sits above the sprinkler manifold outside. This device is an important safety feature that prevents water from flowing backwards into the main supply line. When water is trapped inside the brass bell assembly, it can freeze and break the plastic poppet and bonnet assembly inside. In extreme cases, frozen water can also crack the brass itself. While the internal components can be easily replaced by removing the top of the valve, cracked brass means the entire unit must be replaced.

Damage to Sprinklers

• Sprinkler heads use water pressure to lift a supply tube above the ground. Unless properly drained each season, this water can remain in the sprinkler body. Because the tops of sprinklers are exposed to the outside air, they are especially susceptible to freezing. Frozen water inside a sprinkler head can burst the nozzle, supply tube or the entire sprinkler body. A broken sprinkler will likely gush water rather than spray in a proper pattern.

Prevention

• Preventing cold weather damage to your sprinkler system requires you to remove water from the system before it freezes in the fall. Air compressors can be hooked up to most vacuum breakers to blow out the system. Some systems also have a simple drain valve attached to the manifold that can release much of the water inside the system. Draining as much water as possible will minimize the chance of cold weather damage.