January 10th, 2014

Preventing and Thawing Frozen Water Pipes

Home Owners Network

The recent storms and cold weather have brought our first frozen water pipe questions of the season here at Homeowner’s Network. This emergency edition of our member newsletter will give you some advice about how to prevent frozen water pipes and what to do if the pipes freeze in your home.


The Problem 

Frozen pipes are more than just annoying. Water expands when it freezes and that expansion is strong enough to break pipes. The resulting damage to the pipes and water damage to surrounding materials can be very costly to repair.

Water in pipes exposed to temperature below 32° F. will freeze. This applies to water in supply pipes and in drain pipes, so don’t ignore your drain pipes.

While frozen pipes can occur at any temperature below 32° F., pipes in heated homes are more likely to freeze below about 25° F. This is because heat in the home will usually keep the temperature above freezing in places where the pipes are installed until the temperature drops well below 32° F.

Pipes located in exterior walls, in ventilated crawlspaces and attics, in unheated basements, and in garages are the most likely to freeze. You should direct your attention first to pipes in these areas.


Prevention is the best cure, so here are some steps you can take right now to help prevent frozen pipes.

  1. Turn off the water supply to hose connections. Many homes in cold climates have a valve inside the basement or crawlspace that will shut off water to the hose connection. Look for this valve a few feet before the hose connection. Open the hose valve to drain any water in the pipe.
  2. Leave a small stream of water running in sinks located on exterior walls. A stream about the size of a small pencil will do.
  3. Open cabinet doors at sinks located on exterior walls. This will let warm air circulate near the pipes and helps keep the temperature above freezing.
  4. Close crawlspace ventilation openings. This may help keep the temperature in the crawlspace above freezing. Don’t forget to reopen them in the spring. If you have a gas or oil furnace in the crawlspace or basement, leave a couple of vents open to provide combustion air.
  5. Insulate accessible pipes. Most home center stores sell foam pipe insulation. It comes in pieces about three feet long and easily slips over pipes. Don’t forget to insulate exposed plumbing traps in crawlspaces, unheated basements, and garages. Water will freeze and crack a trap creating a leak that you may not discover for a while. Don’t get this insulation too close to a heat source like a gas water heater vent.
  6. Don’t turn the heat down too far on very cold nights. If you leave on vacation, do not lower the temperature below 55° F. and turn off the water supply at the main water shutoff valve.
  7. Put some trouble lights with incandescent bulbs near vulnerable pipes. One hundred watt bulbs generate a lot of heat. Be sure to use intact extension cords and plug them in to GFCI protected receptacles.


Homes catch fire every year when people try to thaw frozen pipes using some type of flame. Do not use any type of fire-producing device, such as a torch or a gas heater, to thaw frozen pipes. Any fire-producing device creates a fire risk and a carbon monoxide risk.

Open the faucet to let water start flowing once the pipe thaws. Use heat tape, a heat gun (used to remove paint), or even a heating pad to warm an accessible pipe. Warming the area using an electric radiant heater can be effective. Be careful. Do not use these methods on any plastic pipe. Do not use the heat gun too long near wood. Keep close watch on your efforts. If the pipe has broken, water will start flowing once the frozen spot thaws. Damage can occur quickly.

Find Your Water Shutoff Valve

If you don’t know where your main water shutoff valve is located, you should find it now. You will need to shut off water quickly if a pipe breaks. This valve is often located near where the water service pipe enters the crawlspace or basement. It may be in a closet or in the garage.

You should carefully try to turn the valve. Do not apply too much force. Valves that have not been used in years are often stuck and will not turn, or they may leak when turned. If the valve is stuck or if it leaks, call a plumber and have it replaced.

The Bottom Line

You can prevent most frozen pipes with a little effort and planning. You can often thaw frozen pipes yourself with a little care.

We’re here to help at Homeowner’s Network. Use our Ask The Experts service if you need help. Please include as many details as possible about your situation so we can provide you with our best advice.

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