Water expands as it freezes. This expansion causes extreme pressure on whatever is containing it, including pipes, and can cause them to break.
Pipes that freeze most frequently are: - Pipes that are exposed to severe cold, like outdoor hose bibs, swimming pool supply lines, and sprinkler lines. - Water supply pipes in unheated interior areas like basements and crawl spaces, attics, garages, or kitchen cabinets. - Pipes that run against exterior walls that have little or no insulation.
Protecting Your Pipes From Freezing:
A frozen garden hose can cause more damage than a busted hose; it can actually burst interior pipes. When the water in the hose freezes, it expands, increasing pressure throughout the whole plumbing system. As part of your regular seasonal maintenance, garden hoses should be disconnected, drained, and stored before the first hard freeze.
If you don’t have frost-proof spigots, close the interior shut-off valve leading to that faucet, open and drain the spigot, and install a faucet insulator. They only cost a couple of dollars and are worth every penny.
Drain water from swimming pool and sprinkler supply lines (following manufacturer's or installer's directions). Do not put antifreeze in these lines unless directed. Antifreeze is dangerous to humans, pets, wildlife, and landscaping. When the weather is very cold outside, let the cold water drip from the faucet served by exposed pipes. Running water through the pipe - even at a trickle - helps prevent pipes from freezing.
How to Thaw Frozen Pipes
If you turn on a faucet and only a trickle comes out, suspect a frozen pipe. Keep the faucet open. As you treat the frozen pipe and the frozen area begins to melt, water will begin to flow through the frozen area. Running water through the pipe will help melt ice in the pipe.
Apply heat to the section of pipe using an electric heating pad wrapped around the pipe, an electric hair dryer, a portable space heater (kept away from flammable materials), or by wrapping pipes with towels soaked in hot water. Do not use an open flame device.
Apply heat until full water pressure is restored. If you are unable to locate the frozen area, if the frozen area is not accessible, or if you can not thaw the pipe, call a licensed plumber.
Check all other faucets in your home to find out if you have additional frozen pipes. If one pipe freezes, others may freeze, too.
In cases where the location of the frozen pipe cannot be located or it is not accessible, it is best to call a licensed plumber.