When the weather gets cold and you lose your supply of water to frozen pipes, you could face an expensive plumber's bill or water damage to your home. It is often possible to fix on your own, though you should take care to avoid many possible problems, like causing pipes to burst or melt. Before you start trying to heat the ice, you should do a little safety preparation to try to minimize the chance of damage.
Inspect Your Pipes
To fix a frozen pipe, you should find out where the frozen water is concentrated; trying to warm up the entire length of pipe is tedious and ineffective. You can find frozen areas by tapping on the pipe and listening for sections that don't sound hollow. Finding these areas helps you decide what tools you can safely use. For example, while you can use a blow dryer on copper pipes in an open area of your basement, you should not use one on plastic pipes underneath your bathroom sink.
Also look for any signs of cracking. Because water expands when it freezes, much of the damage to your pipes can occur before water flow has even been restored. In addition, if a pipe is cracked, melting the ice inside can cause the pipe to burst and flood. If a frozen pipe is cracked, you shouldn't try to warm it; if you want to try anyway, just be sure you know where the shutoff valve is in case you need to quickly turn off your water.
Open Your Faucets
A frozen pipe causes a buildup in water pressure, and that water will need somewhere to go after the pipe has been unfrozen. To alleviate this issue, open your faucets slightly before you get to work. Don't open them all the way, as this can cause a sudden flood of water, but opening them halfway (or to a drip) can allow water to escape.
You can also shut off the main water supply to your house to prevent any additional water from entering the pipes before you've finished working.
Use a Space Heater
A space heater is a less severe method of warming your pipes; it can take longer, but it avoids the focused heat of a blow dryer. Warming the ice more slowly can reduce the chance of damage, and it can also affect pipes that are inside nearby walls that you can't reach by hand. They are most effective under sinks and in enclosed spaces where they can quickly warm up the whole area by a noticeable amount. Space heaters are also safer for plastic pipes than applying direct heat.
Pads and Towels
Another safe method of applying heat is by wrapping the affected areas in an electric heating pad or towel soaked with hot water. Even once some water flow has been restored, you should keep this up until full water pressure has been restored so you can verify that most of the ice has been dissolved.
Add Pipe Insulation
It may not seem like pipe insulation will do much if your pipes are already frozen, but using it in conjunction with applying heat to the frozen area can help keep the pipes warmer longer, and can reduce the risk that they will freeze again. Adding insulation also helps in older houses because many older pipes don't come with any of their own insulation.
When to Call a Plumber
Sometimes a plumber may be necessary. If you are unable to reach the frozen pipes because they are in the walls or under the floor, or if you have been trying unsuccessfully for hours, a professional will be able to help fix the problem effectively. You should also consider a plumber if you aren't comfortable using tools or if you don't want to risk causing any damage to your home.