how do pipes freeze and burst water pipe and valve

How do pipes freeze and burst?

Author: swartzcontracting November 8, 2017

With the presence of winter weather, the threat of freezing pipes is on many homeowners’ minds.

Pipes burst mainly for one reason: water expands when it freezes. Although, the expansion itself isn’t what causes the pipe to burst. The ice can cause blockage that stops the water flowing downstream. Then the high pressure from the blockage has a chance of bursting the pipe.

But how do we stop pipes from freezing? We hardly ever see them, so keeping an eye on them is not exactly a priority.


Most homes in the northern U.S. are built so that their water pipes are inside of the home’s insulation. This allows them to stay warm and unblocked. However, some pipes are located in attics, crawl spaces, or other areas that lack insulated walls. If there are cracks or spaces that allow for cold air to flow across the pipes, they are at an increased danger of freezing.

Plumbers can reroute dangerous pipes to avoid the danger of freezing, like a bypass. But this method can be impractical. What can usually be done is adding insulation sleeves that wrap around the pipe and help protect it from freezing air.

Turning on the Faucet

During bouts of cold weather, it can be a good idea to let your faucet drip for a few hours. The slow flow of water can prevent the water from freezing in the pipes. Although, this method wastes water, so it should be done only with the faucets connected to in-danger pipes.

If the dripping suddenly stops, leave the faucet on, because this could be a sign that a pipe has frozen and needs to release pressure. It may be a good idea to call a plumber at this point.

Keeping the Heat On

If you are leaving your home for an extended period of time during the winter, hold off on lowering the thermostat. It’s okay to lower the heat, but too little heat during cold weather can put even the safe pipes at risk of freezing. According to the Insurance Institute for Business and Home Safety, the temperature “alert level” is 20 degrees Fahrenheit.

Another way to avoid freezing is to drain the water system. This is useful when you are leaving the house for an extended amount of time. Simply shut off the water main valve in your home, then turn on every faucet and water source until they run out of water. It’s a good idea to leave them on, because the pipes will be full of air at that point and they cannot freeze.

For more on how to protect your home, go through this Pre-Vacation Checklist.

What to Do If Pipes Freeze (Just in Case)

If your water stops running suddenly, or a pipe has burst, don’t hesitate to call a plumber. Shut off the water at the water main valve, and leave faucets on until the plumber has made repairs. (And if there’s water damage as a result, just give us a call.)

Remember to be safe before disaster even has a chance to strike. Keep your water flowing during cold months, protect vulnerable pipes, and always be aware of the weather.