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What Temperature Do Pipes Start to Freeze at Home?

Last updated October 31, 2026

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The short answer

Why 20 Degrees Is the Danger Zone

Water in pipes freezes when it loses enough heat to the surrounding air. That usually happens when the air temperature falls to about 20 degrees Fahrenheit. At that point, the water in exposed or poorly insulated pipes can start to form ice crystals.

The risk grows the longer the cold lasts. A few hours of below-freezing weather is often enough to cause trouble. Pipes near exterior walls, in unheated crawl spaces, or in attics are the most vulnerable. Knowing where your pipes run helps you prepare for cold snaps.

How Insulation and Location Change the Risk

Insulation slows heat loss, so a pipe wrapped in foam or fiberglass can resist freezing at lower temperatures than a bare pipe. Pipes running through heated parts of your home, like a kitchen cabinet, are less likely to freeze than those in a garage or attic.

Even a small draft can lower the temperature around a pipe. Seal gaps around exterior vents, doors, and windows. Keep the garage door closed if you have pipes there. A simple trick is to let a faucet drip slowly, as moving water is harder to freeze.

  • Wrap exposed pipes in foam insulation sleeves.
  • Seal cracks and gaps in walls and floors near pipes.
  • Keep your thermostat at a consistent setting, even at night.
  • Open cabinet doors under sinks to let warm air reach pipes.
  • Disconnect and drain outdoor hoses before cold weather.
  • Know where your main shutoff valve is, in case a pipe bursts.

What to Do When Temperatures Drop

When a freeze warning is issued, take action early. Let cold water drip from faucets connected to exposed pipes. Open cabinet doors to let warm air circulate. If you have a pipe that is already frozen, do not use a torch or open flame to thaw it.

A hair dryer or a space heater can slowly warm a frozen pipe. Start from the faucet side and work toward the frozen section. If you hear a hissing sound or see water leaking, turn off the main water valve immediately. Then call a plumber for help.

Damage from Frozen and Burst Pipes

When water freezes, it expands, which can crack pipes or burst joints. The damage often shows up after the ice melts, when water suddenly flows and floods your home. Even a small leak can soak drywall, floors, and personal belongings.

If you discover a burst pipe, turn off the water supply right away. Then dry the area as quickly as you can to prevent mold. You may need to remove soaked carpet or drywall. Local water damage pros can help with the cleanup and drying process.

  • Turn off the main water valve if a pipe bursts.
  • Mop up standing water and use fans to dry the area.
  • Remove soaked rugs and furniture to speed drying.
  • Check for sagging ceilings or bulging drywall.
  • Take photos of the damage for your insurance records.
  • Call a mold professional if moisture lingers for more than 48 hours.

When to Call the Pros

You can handle minor leaks and drying on your own, but major water damage is a different situation. If water has soaked through walls, floors, or ceilings, you need equipment that most homeowners do not have. Industrial fans, dehumidifiers, and moisture meters are tools the pros use.

The pros can also inspect for hidden damage behind walls and under floors. They can remove wet drywall and flooring safely. If you have a burst pipe, they can help with the cleanup. For urgent situations, contact them as soon as you can. Policies vary, and your insurer decides what is covered.

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Water keeps spreading into floors and walls, so it is worth acting early. Calls are answered 24/7.

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Frequently asked questions

At what temperature do pipes freeze inside a house?

Inside your home, pipes usually freeze when the air around them drops below 32 degrees Fahrenheit. But because most homes are heated, the risk is lower unless the heat is off or the pipes are in an unheated area like a garage or attic.

How long does it take for pipes to freeze at 20 degrees?

It can take several hours for pipes to freeze at 20 degrees, depending on insulation and location. A bare pipe in an unheated crawl space may freeze in a few hours, while an insulated pipe in a heated wall might not freeze at all. Acting quickly is key.

What should I do if a pipe freezes?

First, turn off the water supply at the main valve. Then gently warm the pipe with a hair dryer or space heater, starting from the faucet side. Never use an open flame. If you see a crack or leak, call a plumber right away.

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