When I inspect a house that has a sprinkler system, the report always has a section about protecting the exposed pipes from freezing.  In the Not Hot season, this usually is not an issue. But if it is cold enough long enough, pipes will freeze.  Imagine my surprise and embarrassment when I went outside to get something from my truck and discovered the running water, coming from the exposed pipes of my sprinkler system.  I had drained the back flow preventer, but there was still some water in the pipe.  It cracked the pipe and also the valve.  Unfortunately, we all have lessons to learn, and this is how we gain experience. Even after years of experience…