[header] How to winterize a vacant home [title] Turn off the water at the exterior. [step] Make sure that the water supply is turned off completely at the main supply point. If the furnace should fail on a very cold day, water in a pipe could freeze and burst the pipe. 
[title] Open all faucets and drain all waterlines. [step] If you live in an area where freezing pipes can be a problem, drain the toilets, the water heater (turn off the gas or electric supply first) and the expansion tank.