Frozen pipes? How to prevent them and how to fix them

frozen pipe
© Michael Regan/ Getty Images

It's cold out there; be prepared.

It's cold out there; even in the northeast and in Canada where people are used to it, it is colder than it has been in decades, and it is likely to get colder. Many of our homes were not designed for this kind of cold, and it is possible or even likely that water pipes might freeze. It will be a bigger problem in the parts of the country where this kind of cold is really unusual; up north, builders don't put pipes in outside walls, and everybody knows to shut off the hose bibs that run outside. Further south, not so much; the most vulnerable houses are in the usually warmer climates.

Both plastic and copper plumbing can freeze, but copper is more likely to burst. This happens when the pipe totally freezes, since water exerts 2,000 pounds per square inch of pressure when it expands as ice. Pipes are most likely to freeze in cabinets under sinks on outside walls, in unheated crawl spaces or basements, or where they are plumbed in outside walls where it supposedly doesn't freeze. So the first thing you should do is:

open the doorsState Farm Insurance/ Open the doors below your sinks if they are on an outside wall/CC BY 2.0

Before the freeze

  • Learn where your water shut-off is. You may have never had any need to turn off the water in your home, and may not know where the valve is; there is one somewhere where the water comes into your home and you may need it.
  • Shut off those outside hose bibs. Modern ones have long shafts and take care of themselves, but older homes may have an interior shutoff valve.
  • Open all cupboard doors under bathroom vanities and kitchen sinks. Make sure any dangerous cleaning stuff is removed if you have kids.
  • This is not at all TreeHugger correct, but open a tap and let it drip a bit. If the water is moving, it won't freeze. Run cold water (very slowly) from the lowest point in the house, into a laundry tub if you have one. I know people who have let it run into a bathtub because they didn't want to waste the water; when it warmed up they used the water for flushing toilets with a bucket.

In case of a freeze

You may notice that the water is really slow from a tap, or just stops flowing. If it is just one faucet then the problem is probably local. There are a number of ways to thaw the pipe: Open the faucet so that water can run when you thaw the pipe.
  • Hot water: wrap a hot wet towel around the pipe, try and catch excess with a bucket.
  • Hair dryer or paint remover gun or heat lamp: this is the safest way to do it. Blow it on the pipe until the water starts running.
  • Then there is the technique that I use but every usual site says DON'T DO THIS: a propane torch. If you do this, try and put some fireproof material behind the pipe. Move the torch a lot, never keeping it in one spot on the pipe and keep far away from connections. And only if you have some experience with plumbing.

If a pipe bursts:

Turn off the water at the shut-off; open up some taps to release any pressure; call the plumber and hope she is not too busy. I have done my own repairs but unless you have experience, it is a good way to burn down the house or make things worse.

Long term prevention:

This doesn't happen in a properly insulated and sealed house; I suspect that no Passive House designs ever got a frozen pipe.
  • Never put pipes in an outside wall, and avoid putting bathroom vanities on outside walls; I did this in my Mom's cottage and this is where I learned how to solder and fix pipes.
  • If a pipe is particularly susceptible to freezing, put electric heat tape and insulation on it.
  • Modern plastic plumbing is less likely to burst when it freezes; use instead of copper.

Other cold-weather tips

gas ventLloyd Alter/ gas vent on my house/CC BY 2.0
If you have a gas furnace with outside combustion air, make sure it doesn't get buried in ice and snow. Here's mine, with ice from condensate building up underneath. If it gets high enough to block the vent it could kill us all from carbon monoxide.

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