Power outages and winter temperatures can result in frozen pipes. Thawing frozen pipes is a slow, time-consuming but necessary process.
First stepsBefore starting to thaw a frozen pipe, close the shut-off valve to the pipe or the main shut-off valve for the house. This will prevent water from gushing out as soon as the pipe is thawed.
Water expands as it freezes, so frozen pipes or joints may burst or leak. Check for breaks and repair them before defrosting the pipe.
Also, open the faucets connected to the pipes so that water and steam from the melting ice can escape when the pipe is heated. Close the faucets when the pipes have thawed.
Which pipes are frozen?
If no water runs from any faucet in the house, a main inlet pipe near the water meter may be frozen. To confirm this, touch the meter and exposed pipes adjacent to it. If they feel extremly cold, a main inlet pipe probably needs thawing.
When water runs in only one part of the house, a pipe in an adjacent outside wall or uninsulated crawl space may be frozen. Turn up the heating system. Open kitchen and - if needed - bathroom sink cabinets to let in the warm air to the pipes. Or heat the pipes where they emerge from the wall.
How to thaw pipes
If possible, let nature take its course and allow frozen pipes gradually to thaw on their own after heat is restored to the house. Of course, this may require more time than you're willing to be without water.
If a pipe is partly frozen, open the affected faucet all the way. Then open other hot-water faucets in the house. This will raise the temperature of the water in the hot-water pipes and help melt the water in the nearly frozen pipe. Once hot water is flowing from all the faucets, close them to a trickle. Don't turn the faucets off completely until water is flowing freely from the affected faucet.
To keep a frozen pipe from bursting while heating it, it's important not to warm the pipe any hotter than your hand can tolerate. Never allow a pipe to get too hot to touch. If the water in the frozen pipe begins to boil, the pipe may explode.
Other thawing methods
Here are some other tried-and-true ways to thaw a frozen pipe:
- Thaw a well-in pipe slowly with a heat lamp clamped to a chair or ladder and set a few inches from the wall.
- Wrap rags around a metal pipe (but not plastic pipe), and pour near-boiling water over the rags. (Place a container under the pipe to catch the runoff.) Repeat when the rags cool.
- Wrap a grounded waterproof heating pad, electric blanket or heat tape set to its lowest temperature around a frozen metal or plastic pipe.
- After opening the nearest faucet, use a heat lamp or hair dryer to warm the pipe. Warm the pipe gradually, working back from the faucet toward the frozen area.
- A propane torch with a flame spreader can also be used. Because of a propane flame's concentrated heat, it's extremely important to use a flame spreader and not allow the pipe to get too hot to the touch.
CAUTION: Never use a propane torch on a plastic pipe.
Preventing frozen pipes
During a winter cold snap, open all faucets a little. A steady drip may be enough to keep the water from freezing. Even if the pipes do freeze, the open line will often keep them from bursting.
Install pipe insulation or wrap exposed pipes with strips of foil-faced fiberglass batts, foil side out, and secure the batts with duct tape. (Wear gloves when handling fiberglass.)