Why Do Water Pipes Burst in the Winter?

By Winters Home Services

Boston is known for being quite chilly (and snowy) in the wintertime, but that doesn’t stop its residents from making the most of the winter weather. From the Holiday Bricktacular at LEGOLAND® to the Festival of Lights at the Museum of Fine Arts, to Santa Saturdays at the Franklin Park Zoo, to Snowmazing! at Boston Children’s Museum, to Mikko Nissinen’s The Nutcracker by the Boston Ballet, there’s loads to do in Boston despite the ice and snow.

All the fun stuff aside, we can’t forget about what the icy cold temperatures can do to our plumbing pipes. If we neglect our pipes and they freeze, we can come home to a disastrous flood that can quickly ruin our holiday cheer and our budget. So, why do pipes burst in the wintertime? What is the science behind freeze breaks? And most importantly, what can be done to prevent them?

Why Do Pipes Burst in Winter?

Contrary to popular belief, it's not because of ice expanding inside the pipes. Without going into too much scientific detail, when water freezes inside pipes, the water molecules expand. The ice then expands and pushes the water toward the faucet, causing a significant amount of pressure buildup between the ice blockage inside the pipe and the faucet. Eventually, the pipe can’t take the pressure buildup and it bursts. The rupture usually occurs in a location in the pipe where there’s little to no ice.

Which Pipes Are at Risk?

The more that pipes are exposed to freezing temperatures, the greater the risk of them bursting during the winter months. The pipes at the greatest risk include:

  1. Pipes that are not insulated, and
  2. Indoor pipes that are in unheated areas, such as basements, attics and crawl spaces. This is why so many freeze breaks occur in basements, leading to floods.

The best way to prevent frozen burst pipes is to insulate vulnerable pipes with foam or fiberglass sleeves. Also, keeping the faucet open and letting the water run just a trickle can help by preventing the water pressure from building up.


Call Winters Home Services today at (617) 977-3101 or contact us online if you are dealing with a burst water pipe in your Boston home.