If you have an RPZ valve installed on your water line, it is your responsibility to make sure that it is properly insulated for extreme low temperatures.

If your valve is tied off of your water line to your house to serve an irrigation system, swimming pool, or other non-sewered service then you should cut the valve off and properly drain it for the winter. A new law became effective July 1, 2010 that all homes are required to have separate water meter if you have in-ground irrigation or swimming pool.