Water freezes at 32 degrees or colder, but multiple factors impact whether pipes will freeze.
Pipes in 20 degrees or colder for prolonged periods will freeze.
Exterior pipes freeze much faster than internal pipes.
Insulating hot water pipes can raise the water temperature by 2 to 4 degrees.
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If a cold front is about to strike, you may be wondering if your pipes are at risk of freezing. While water freezes at 32 degrees Fahrenheit or lower, what temperature pipes freeze at depends on multiple factors. In addition to outdoor temperatures, whether pipes will freeze depends on location, how insulated they are, where you live, and how long the temperature stays at or below freezing. Here’s everything you need to know about frozen pipes, how to prevent them, and what to do if it happens.
Angi Tip
Thawing a frozen pipe before it bursts is crucial. We recommend contacting a plumber to ensure your pipes are thawed effectively. If a pipe were to burst, it would likely require an expensive repair.
Pipes run the risk of freezing at temperatures below 32 degrees, especially if they're not insulated, but most insulated pipes start to freeze at 20 degrees or below. When temperatures drop below 20 degrees, it usually takes six hours for insulated pipes to freeze, while temperatures between 20 and 32 degrees are likely to freeze pipes after about 12 hours. Knowing how long a freeze can take to set in can help you keep your pipes from freezing.
Temperature (F)
Temperature (C)
32 degrees
0 degrees
20 degrees
-6.6 degrees
0 degrees
-17.7 degrees
Remember that these are outdoor temperatures rather than your pipes’ temperatures. In other words, an outdoor temperature of 20 degrees isn’t necessarily going to cause the pipes on your property to freeze.
When water freezes, it expands, which can create pressure in your pipes and cause them to burst. So your pipes can potentially burst when temperatures drop below 32 degrees. However, the time it will take for them to burst depends on just how cold it is and for how long. A quick cold snap isn't likely to make them burst, but if temperatures are very low for more than four to six hours, your pipes can burst.
The weather forecast is in, and you see upcoming prolonged periods of below-freezing temperatures. Even with the most ambitious measures, your pipes can still freeze, so knowing how to find frozen pipes can help you prepare for worst-case scenarios.
Keep an ear out for whistling or clanking sounds inside pipes, and pay attention to suspicious smells. Inspect accessible pipes to look for bulging, cracking, ice, drips, and water spots on the ceiling or walls.
When water freezes, it expands, leading to burst pipes. At the first sign of frozen pipes, take action to thaw your pipes. Here’s what to do if your pipes freeze:
Keep your faucets on (even if the water stops coming out).
Use a hair dryer, space heater, electric heating pad, or hot towels to thaw the pipes.
Continue to apply heat until water comes out of your pipes again.
Check all other faucets to find frozen pipes and repeat these steps if necessary.
Just a note: You should never attempt to thaw a frozen pipe using an open flame, as this can be extremely dangerous. It’s also not a good idea to pour boiling water down a drain pipe or on the outside of pipes, as this water can freeze and make the issue worse.
As confusing as it may be to figure out which temperature will cause your pipes to freeze, there are several ways you can determine whether your home is at risk of freezing pipes come winter.
Your geographic location: Where you live impacts your home’s design and can impact the temperature at which your pipes freeze. Homes in the North, for instance, are designed to protect against freezing, while homes in the South aren’t as well insulated.
Pipe location: Pipes located on the exterior of the home are more susceptible to freezing temperatures. Exposed pipes may freeze after a few hours in 20 degree temperatures, but it can take longer in 32 degrees or higher—sometimes around half a day. Interior pipes are less likely to freeze, but they’re still susceptible if they’re on an exterior wall and may freeze after 2 to 3 hours. Pipes further inside the home can take 6 hours or more to freeze in temperatures below 20 degrees.
Level of insulation: According to Energy Saver, the best pipe insulation to prevent freezing can raise your water temperature by 3 to 4 degrees. You can insulate pipes with heat tape or different forms of insulation: spiral-wrap, fiberglass, spray foam, and self-sealing foam.
Type of pipes: Some pipes simply freeze faster than others. Copper pipes freeze faster than PEX piping, which has more freeze resistance. Copper is a good conductor of heat, so heat loss occurs faster.
Overall temperature: If the temperature only drops below freezing for a few hours, your pipes might not have enough time to freeze. On the other hand, sustained temperatures below 20 degrees—especially for six or more hours—will likely result in frozen pipes without preventative measures.
Taking steps to prevent your pipes from freezing can be a DIY job, but if a pipe bursts, you’ll need to hire a pro. You can prepare for cold temperatures by disconnecting hoses from outdoor pipes, winterizing outdoor faucets, and insulating pipes close to the home’s exterior. Opening your cabinets and dripping your faucets if temperatures dip below 20 degrees can also reduce the likelihood of your pipes freezing.
If a pipe does end up bursting, hire a local plumber to assess the situation and complete the repairs. They’ll be able to locate the burst pipe, ensure the other pipes are in good condition, and offer suggestions for preventing the problem in the future.
Cost to Repair Burst Pipes
The cost to repair a burst pipe is $500, on average, if you choose to hire a plumbing repair pro. While you might think you can DIY this repair to save money, we highly recommend hiring a plumber to understand the root cause of the issue causing the pipe to burst and ensure that the job is done correctly the first time. Plumbing repair mistakes can lead to water damage and further problems—all of which will likely cost more than if you hired a professional to fix the issue from the get-go.
Frequently Asked Questions
Pipes can freeze in one night, depending on the temperature and location of your pipes. If the temperature is below 20 degrees, your pipes could freeze in under six hours. Well-insulated pipes might take longer to freeze, but you should follow local guidelines for preventing frozen pipes. How quickly your pipes can freeze can also depend on where you live and the type of pipes.
How long it takes for a pipe to freeze depends on the outdoor temperature, the level of preventative measures taken, and how long the outdoor temperature stays below freezing. With this in mind, expect most pipes to freeze within six to eight hours. Uninsulated exterior pipes can freeze in under six hours if the temperature is below 20 degrees. It takes at least 12 hours for unprotected pipes to freeze at 32 degrees.
If you're planning to go out of town and you're worried that the temperatures will drop below freezing while you're gone, it's a good idea to set your heat to no lower than 55 to 60 degrees. In most areas, this will provide enough warmth to help prevent your pipes from freezing.
A burst pipe can cause hundreds or even thousands of dollars in damage. It could flood your home, which can destroy many of your belongings. It could also ruin hardwood floors and carpeting, requiring you to replace your flooring. Finally, mold and mildew form very quickly after high levels of moisture have been introduced to a space; this is not only costly to remove but also bad for your health.
Stephanie Mickelson is a freelance writer covering home improvement, real estate, design, and personal finance. Before beginning her freelance career, she worked in residential construction, specifically remodeling kitchens, installing cabinets, flooring, countertops, trim, and more.
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