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How to prevent frozen pipes and thaw them safely

A few easy steps before a cold snap can save you from a burst pipe and a flooded house. If a pipe does freeze, here's how to thaw it without making things worse.

Updated · 6 min read

  • DifficultyEasy
  • Time30–60 minutes to prepare
  • If you need helpPlumber

When water freezes, it expands. Inside a pipe, that can mean a crack or a burst, and when the ice melts, water pours out. A burst pipe can soak floors, walls and ceilings in a short time.

The good news is that prevention is cheap and easy. Most of it takes under an hour before a cold snap: dripping a faucet, opening a few cabinet doors, insulating exposed pipes and putting the garden hose away.

Pipes most at risk are the ones in cold spots: outside walls, crawl spaces, attics, garages, and under kitchen and bathroom sinks on outside walls. Outdoor faucets and sprinkler lines are at risk too.

What you'll need

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Before winter, make sure everyone in the house knows where the main water shutoff is. Our guide to finding your water shutoff shows where to look.

Before a cold snap

These steps come from the American Red Cross's guidance on frozen pipes.

  1. Drip the faucets. When it's very cold, let cold water drip from faucets that are fed by exposed pipes.
  2. Open cabinet doors. Open kitchen and bathroom cabinets so warmer room air can reach the pipes. Move cleaning products out of reach of kids and pets while the doors are open.
  3. Keep the garage door closed. This matters if water lines run through the garage.
  4. Keep the heat steady. Set the thermostat to the same temperature day and night during a cold spell, instead of turning it way down at night.
  5. Leave the heat on when you travel. The Red Cross says to keep it set no lower than 55°F. Our before-you-travel checklist covers other steps.

Insulate exposed pipes

The Red Cross suggests insulating both hot and cold water lines in unheated areas, like garages, crawl spaces and under sinks on outside walls. Adding insulation to attics, basements and crawl spaces also helps keep those spaces warmer.

  1. Find the pipes. Check the crawl space, garage, basement and any pipes along outside walls.
  2. Slip on foam sleeves. Buy the size that matches your pipe and fit them snugly. Tape the seams if needed.
  3. Use heat tape for the worst spots. For pipes that freeze often, the Red Cross mentions UL-listed heat tape or heat cable. Follow the maker's instructions exactly.
  4. Seal drafts. Cold air leaking in near pipes can freeze them even in a heated home. Sealing gaps around the house helps.

Outdoor faucets and hoses

  1. Disconnect hoses. Remove, drain and store garden hoses. A connected hose traps water in the faucet.
  2. Close the indoor valve. Many homes have a shutoff inside that feeds each outdoor faucet. The Red Cross says to close it, then open the outdoor faucet so any trapped water can drain and expand without breaking the pipe.
  3. Drain sprinkler and pool lines. Follow the manufacturer's or installer's directions.
  4. Cover outdoor faucets. An insulated cover adds a little protection.

If your outdoor faucet already leaks, see our guide to an outdoor faucet that's leaking.

If a pipe freezes: how to thaw it safely

The Red Cross says to suspect a frozen pipe if you turn on a faucet and only a trickle comes out.

  1. Leave the faucet open. As the ice melts, running water helps melt the rest.
  2. Find the frozen spot. Look along the pipe from the faucet back toward where it enters the house. Frost on the pipe or a section along an outside wall is a good clue.
  3. Apply gentle heat. Use a hair dryer, an electric heating pad, or towels soaked in hot water. A portable space heater can help too, kept well away from anything that can burn.
  4. Never use an open flame. No blowtorch, propane or kerosene heater, or charcoal stove.
  5. Keep going until full pressure returns.
  6. Check other faucets. If one pipe froze, others may have too.
  7. Watch for leaks. A pipe can crack while frozen and only leak once it thaws. Keep an eye on it and know where your shutoff is.

When to call a pro

Call a licensed plumber if:

  • You can't find or reach the frozen section, or you can't get it to thaw. The Red Cross recommends a licensed plumber in this case.
  • A pipe has cracked, burst or is leaking. Shut off the main water first.
  • Pipes freeze in the same spot every winter. A plumber can reroute or protect them.
  • The frozen pipe is inside a wall or ceiling.
  • You rent. Tell your landlord right away, and ask before adding heat tape or insulation.

Read how to choose a plumber, or take our fix it or call a pro quiz.

Keep it from happening again

  • Work through our winter home maintenance checklist each fall.
  • Put hoses away and shut off outdoor faucets before the first hard freeze.
  • Add insulation to pipes that froze before.
  • Keep the heat at 55°F or higher when you're away.
  • Put the main water shutoff location on our free home emergency card.

Common questions

Should I drip my faucets when it's freezing?

The American Red Cross says that when it's very cold, let cold water drip from faucets served by exposed pipes. Moving water helps keep a pipe from freezing.

What temperature should I leave my house at when I'm away in winter?

The Red Cross recommends leaving the heat on, set no lower than 55°F, if you'll be away during cold weather.

How do I know if a pipe is frozen?

If you turn on a faucet and only a trickle comes out, the Red Cross says to suspect a frozen pipe. Check other faucets too, since if one pipe freezes, others may as well.

Can I use a torch to thaw a frozen pipe?

No. The Red Cross warns against using a blowtorch, kerosene or propane heater, charcoal stove or any open flame. Use gentle heat like a hair dryer, heating pad or towels soaked in hot water.

Sources

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