Yes. Winterizing your irrigation system involves, first, closing the main water valve for your sprinkler system and, second, using a commercial sized air compressor to blow air through all of the irrigation pipes. This clears out all of the water sitting in the pipes. If the system is not winterized and temperature drops to freezing, you are very likely to have irrigation pipes burst. This can lead to thousands of dollars in repairs to get the irrigation system back to functioning.