Winter in the Northwest is mild compared to other parts of the country, though we are still at risk for freeze damage. So what exactly are the risks for homeowners in the winter? That answer can matter if the home you are referring to is vacant or occupied.
In Occupied Homes:
If you are living in the house and heating it, all you should need to worry about are the elements that will be exposed to the cold. Hose bibs and outside taps that are filled with water should be contained by an insulated cover. If it has a sill-cock, it means that the water is stopped from entering the house and there is less risk of a frozen pipe. It is still a good idea to cover those just to be safe. Any exposed pipe that has water in it has the potential to freeze. When water freezes, it expands and can cause the pipe to burst. You only learn about the crack when it thaws. I once ran a copper pipe under my deck to extend the outside tap to the end of the deck. In the summer, I reconnected it and after realized the pipe had split and I received an unexpected outdoor shower.
If the home is vacant, there are more things to prepare for. First, be sure to keep the house above freezing temperature. This will make sure the indoor pipes don’t burst from freezing but it doesn’t necessarily protect the pipes we forget about under the house. Flowing water doesn’t freeze but standing water in a pipe under an unoccupied home easily could. We also often forget about drains and p-traps. If a p-trap from your bath tub is under your home it could easily crack.
We have had a rental in the Moses Lake area where it can get pretty cold and can be vacant for a few days between tenants. One outgoing tenant turned off the heater and hot water heater thinking to save electricity. The incoming guests got a big surprise. With the hot water heater being in the garage and not staying to temperature, it froze and we had to replace it. At minimum, make sure the main water valve is closed if your property is vacant and when you turn it on, you inspect it for leaks and check the water meter to be sure you don’t have running water.