When winter’s coldest temperatures arrive, some common-sense precautions could prevent your pipes from freezing and possibly bursting—which could lead to water damage and costly repairs.
Insulate water pipes that run through unheated spaces such as a basement, garage, crawl space, or close to exterior walls. Foam pipe insulation sleeves are inexpensive and easy to install. Be sure not to leave any gaps, especially at elbows and T joints, where there is greater risk of freezing.
Seal openings in the basement foundation where cold air can enter by using caulk or insulation foam. Feel for cold drafts near your water pipes, trace them back to the source, and seal the hole or crack. The cold air could cause your pipes to freeze.
Leave cabinet doors open in the kitchen and bathroom to allow warm air from your living space to circulate around pipes inside.
Check and protect your water meter. An open basement door or window can cause the water meter to freeze.
While you’re at it, locate the main water shutoff valve in your home and learn how to turn it off. If a pipe bursts, you can shut off the water to minimize any damage.
Relieve the pressure
If you can’t adequately insulate the pipe, allow a slow trickle of water to flow through the faucet at times when the risk of freezing is high. A tiny drip is enough. Be sure to allow both hot and cold water to flow; if you have a mixer valve, the water should be warm.
It’s a common misconception that frozen pipes burst because of the ice inside pushing outward. William B. Rose, a senior researcher at the Illinois Sustainable Technology Center, explained in a New York Times Q&A that the ice blockage “grows along the length of the pipe and acts like a piston.” When the faucet is turned off, there is no pressure relief downstream, so pressure builds in the pipe. This pressure is the cause of the rupture. “If you can relieve the pressure downstream of the blockage by allowing the tiniest little drip at the faucet, then the ice blockage can grow and it won’t rupture the pipe.”
If pipes freeze
If a pipe freezes, but has not burst, make sure to keep the faucets open. “Ice has created a blockage and it’s still growing toward the fixture. If you shut the faucet, there’s nowhere for the pressure to go, and it can burst,” said Rose. An open faucet will relieve the pressure that can lead to a rupture.
To thaw lines, remove any insulation and apply heat by using a hair dryer. Never use an open flame. A hair dryer “may not be fast, but it will be safe,” according to the Boston Water & Sewer Commission.
If a pipe bursts, shut off the water to that line to prevent additional damage, and contact your plumber.