It is important to winterize and weatherize your sprinkler system before the first freeze sets in and damage occurs.
Reasons to Winterize
If water is left in sprinkler system pipes, then as it freezes—and it will in a cold climate—the underground pipes will expand with the water and eventually burst. This will result in damage to your entire sprinkler system and may necessitate pulling the entire system out of the ground to replace it. Not only is this unnecessary, but it can also be very expensive.
Draining the water out of your sprinkler system is not enough to prevent potential freezing and damage to water pipes. In order to completely winterize the system, you must blow the system clear of all water. This can be done by manually draining the system and then using an air compressor to completely remove any remaining water.
If you have never before used an air compressor to winterize a sprinkler system, it is a good idea to get assistance from someone who has done this annual chore. An experienced person can offer guidance when using the compressor to ensure that you don't damage your sprinkler system.