How to keep pipes from freezing


If a cold snap made your water pipe snap you have a few options on how to prevent it in the future. (The only way to prevent it from happening in the past is to use time travel and that is beyond the scope of this article.)

Outdoor faucets are prone to freezing because they are full of water and exposed to the cold air. The pipe to which the faucet is connected is also at risk for bursting for the same reasons. One approach is to have a dedicated shutoff valve inside the house that will turn off the water to the whole pipe feeding the faucet. When winter approaches, turn off the water using the shutoff valve and then open the faucet to drain the water out of the pipe. Leave the faucet open so that any water that didn’t drain out will have room to expand if it freezes. If there is a lot of water left in the pipe because it has low spots or sections that run uphill on the way to the faucet the pipe could still burst.

If the pipe enters a warm part of the house within a couple of feet of the faucet you can replace the faucet and the last portion of the pipe with a “frost-proof” or “freeze-resistant” faucet. These devices have a long rod between the faucet handle and the valve that stops the water.

When you turn off the water using the faucet handle you are actually turning a valve about a foot or so inside the pipe, which is in the warm area of the house. The pipe should be sloped toward the outside of the house so that any remaining water drains out. With this type of faucet the potentially cold part of the pipe is always empty. Replacing a standard outdoor faucet with a freeze-resistant faucet requires about SkillLevel3


Insulating a water pipe with foam insulation

doesn’t do very much when it gets icy cold because it has an R-value of something like 2. Pipe insulation will slow down the freezing process but won’t stop it.

If more than a foot or so of the water pipe is exposed to the cold air your best bet is to wrap it with heat tape.

The heat tape is plugged into an electric outlet and has a thermostat that turns on the electricity to heat the pipe when the outside temperature drops to about 38 degrees  or lower. It uses very little power. The water pipe can be metal (copper or galvanized steel) or plastic (CPVC, PEX, etc.).

I wrapped heat tape in a spiral around some PEX pipe that was exposed to the outside air.

heat tape around pipe heat tape with insulation heat tape insulatedThen I sealed the pipe with foam insulation to keep the heat next to the pipe when the thermostat turns on the heating wires.

A short extension cord connects the heat tape to the nearest outlet. After it is plugged in you can forget about it because it is totally automatic and will come on only when needed to keep your pipe from freezing.

Living in coastal South Carolina you would think that I have no reason to know any of this information but thanks to the Polar Vortex our water pipe burst last winter. (See “Polar vortex burst my PEX.”) Now I’m ready for Polar Vortex II. Alternatively, I would welcome any suggestions for constructing the time machine.




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