Ensure that the house will not be in use while the water softener is winterized, as shutting down your softener for the winter while the house is still occupied can be hazardous.
Unplug the water softener.
Turn the softener's manual bypass valve, if applicable, to the bypass position. This removes the softener from the water-flow loop.
Drain the water from the water softener's media tank, also known as the ion exchanger tank, if the heat in the building will be turned off. This will prevent the softener from freezing in the cold months of winter.
Remove the drain plug from your water softener's control valve if your softener features a control valve.