In-ground sprinkler systems are incredibly helpful in keeping the grass and garden looking great during the warm months of the year, but when the temperature drops, the water within the buried hoses and pipes is likely to freeze, forcing the pipe to expand and crack. Rigid PVC pipes may burst entirely, instead of developing slow leaks, which is more common with flexible polyethylene pipes.
To help prevent damage to your sprinkler system, it’s important to shut off the flow of water to the system. You also need to make sure to drain the water out of the pipes, so they remain empty throughout the cold winter months. Follow these steps to drain and blow out your sprinkler system, protecting the lines from cracks and leaks.
Only attempt to blow out your sprinkler system if you have experience working with an air compressor. An air compressor can cause extensive damage to the sprinkler system and could put an inexperienced user or others at risk if the air pressure makes the water line burst.
Source: The Spruce