[edpontiac91]

Had the same problem in our attic (our outdoor water lines) froze and busted open with rain from above not being pretty.
I had a plumber install a fitting with an on-off valve and right above was a threaded pipe plug. When you turn off the water for the winter to those lines, open all the outside lines to let the water drain out. Then take out the drain plug and open up the water valve.
What that does it to let any air out of the line and also allows ALL the water to drain out.
Also they sell a pipe wrap that you can plug in and it will keep the pipe warm if you need that line during the winter, like if it's closed off behind a wall.