The best way to prepare the vacuum break for a hard freeze, or if you live in a state that has a hard winter, is to cover all of the exposed pipe with Polyethylene pipe insulation. Shut off the water to the vacuum breaker. Next, loosen the screws on both test ports on the side of the breaker. Allow the water in the vacuum breaker to drain out. This will keep it from freezing, expanding and ruining the internal parts.