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How To Thaw Frozen Pipes

During cold weather, pipes in your walls, attic or under your floor can freeze. Frozen pipes can crack or burst because as water freezes, it expands. With enough expansion, pipes will develop cracks. The cracks may not be visible but they will leak nonetheless when the ice melts. If a frozen section of pipe is caught in time, there may be no damage; but it must be thawed before any more freezing occurs. Protecting pipes from freezing is the best plan, but if you are reading this, then that will have to take a backseat to thawing the frozen pipes. To learn how to prevent pipes freezing in the first place.

Caution: Please read our safety information before attempting any testing, maintenance or repairs. Some equipment may rely on a cold water supply and suffer damage without it.

If there is a slow trickle at the faucet, leave the faucet open. The flowing water will help to prevent a complete frozen blockage. In addition, the flowing water may help to melt the existing partial blockage. Continue with the following steps to ensure the pipes thaw completely.

Locate the Frozen Pipe

The first step to thaw frozen pipes is to locate the section of pipe and turn off the local water supply to it. To determine whether a section of pipe is frozen, simply feel it. Frozen pipe will feel very cold, while pipe with free flowing water will feel notably warmer. Try to find a pipe through which water is still flowing to use as a comparison. After a couple minutes of running, the pipe should be around 50 degrees or so. If you have an infrared thermometer, it makes finding frozen pipes easy.

How to prevent frozen pipes

How to repair a frozen or broken pipe

If there is no water at any of the taps in the house, the main water line may be frozen somewhere between the meter and where the water line enters the house. Typically this line is buried, and buried at the locally mandated depth to protect it from freezing. There is little to be done to thaw a buried water line. The only course of action is to rebury the line deeper, below the frost line, to ensure against future freezes.

In serious freezes, there may be multiple frozen sections of pipe in various vulnerable locations. The first point to inspect is where the water line comes out of the ground and where it enters your home. Any exposed pipe is vulnerable if it is exposed to outside air, even if it is in your attic, unconditioned basement or crawlspace.

Exterior walls, even when insulated, may get cold enough to freeze pipes inside the wall. Pipes that pass near an exterior vent in your home are subjected to colder air and are a good place to start hunting. If there is no water in only one part of the house, then the frozen pipe is probably in an exterior wall, attic, crawl space or basement.

Once you locate the frozen section, if the pipe is accessible, inspect it visually and by running your fingers over the pipe to feel for cracks or splits. If you find damage, you may want to get repair materials ready before thawing the pipe. If the pipe is not accessible, read on for techniques to deal with hard to reach pipes.

Before you start the thawing process, open water taps on the frozen line to allow water, steam or pressure to escape. This will allow water to drain out as the ice melts and will tell you if you have succeeded in melting the obstruction.

How you heat the pipe depends upon the type of pipe and the location. But in all cases start nearest the tap and work outward. Never heat a pipe with direct flame or boiling water. Heating a pipe too quickly can result in bursting, damage and injury.

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