Winterizing your sprinklers is an important task that Trinity Team Management will coordinate for its owners. Here in Colorado we generally schedule blowouts for the first week in October. We hire professionals to complete the job to ensure the pipes do not freeze. If you forget to winterize your sprinklers, you run the risk that water will freeze in the irrigation valves, pipes, and sprinkler heads. When water freezes, it expands causing the parts of your system to burst and destroying your sprinkler system
The cost is approximate (generally $75-90 charge for our companies to take care of winterization). Some of the smaller vendors use a compressor that is not large enough, but they are less expensive. This runs the risk of breaking the blow off valve/vacuum breaker if the compressor they use is not large enough. All the companies we use will use the correct size compressor. Hence, the old saying, you get what you pay for.