Well, it can get to -40'C (extreme) where I live. I blow all the lines out, completely, then I pump the plumbing antifreeze through all the lines, and make sure there is some in all drain traps.
It took awhile to clear everything out in the spring, but I bet fixing a plumbing leak would take longer.
I winterize an inground pool and a bathroom out in the pool house. I read on the antifreeze bottles that you must remove all water or there is a risk of freezing, even if the antifreeze is present. I take this pretty much to heart!
2013 Swift 145RB