Frozen pipes can be a serious threat to your home in the winter. Beyond simply blocking the flow of water in your home's plumbing, the fact that water expands when it freezes means that frozen pipes run the risk of causing your pipes to burst, which can cause water damage once the temperature rises again. Fortunately, there are a few preventative maintenance tasks that you can perform to ensure that your pipes are at a low risk of freezing once the temperature ticks under freezing.
For pipes that are exposed within your home, even if they are exposed within a crawlspace or an out of the way area, you may want to consider installing additional insulation around them. Pipe insulation, which can be installed directly on your plumbing, is available at most hardware stores and can easily cut to size. Otherwise, insulating the crawlspace or area around your plumbing can be just as effective at preventing water inside your plumbing from freezing.
Alternatively, you could also install heating tape directly on your pipes, which can be turned on to provide direct heating to certain sections of plumbing that are particularly at risk of freezing.
Open Cabinet Doors
For certain sections of pipes, including under-sink plumbing, their location near the side of your home and the cabinets that they are installed within can put them at particular risk of freezing. In order to circulate more warm air around these pipes and thus ensure that the water within them does not freeze, you should open the cabinet doors periodically.
Create a Slow Drip
For water fixtures that have plumbing that runs against an exterior wall, but would be hard or prohibitively expensive to properly insulate, you may want to instead leave the fixture slightly open. A drip, however slow, ensures that the water in your plumbing is moving, and thus is much less likely to freeze. Keep in mind, however, that doing so will slightly increase your water bills, which can turn into a fairly significant expense over a long enough period of time.
Drain Exterior Faucets
Outside of your home, you should remove all hoses outside of your home and turn the water supply to outdoor faucets and hose bibs off before the temperature dips below freezing. Once you've turned the water supply off, you should then open the faucet, allowing all the residual water within the pipes to drain out. This will prevent that water from freezing, which can potentially cause a burst pipe and leaking on either the exterior or interior of your home.
To learn more about taking care of your pipes, visit resources like http://www.LewisPlumbingSantaBarbara.com.