USA Expert Plumbing

How to thaw frozen pipes safely

By USA Expert Plumbing Editorial Team. Updated . 2 min read.

Short answer

Open the faucet the frozen pipe feeds, then warm the pipe slowly starting near the faucet with a hair dryer, an electric heating pad or towels soaked in hot water. Keep heating until full pressure returns. Never use an open flame such as a torch. If you cannot find or reach the frozen section, or the pipe has burst, shut off the main water and call a plumber.

In this guide
  1. Before you start
  2. Safe ways to warm the pipe
  3. Pipes inside a wall
  4. When to call a plumber
  5. If the pipe bursts

If a faucet slows to a trickle or stops during very cold weather, a pipe feeding it has probably frozen. Thawing it promptly and safely can prevent a burst.

The steps below follow American Red Cross guidance on frozen pipes, plus manufacturer instructions where noted.

Never thaw pipes with an open flame. Do not use a blowtorch, propane or kerosene heater, charcoal stove or any other open-flame device. They can start a fire and can overheat the pipe.

Before you start

  1. Find the main water shutoff and make sure you can reach it. If the pipe has already cracked, water will flow as it thaws.
  2. Open the faucet the frozen pipe serves. As the ice melts, water flowing through helps thaw the rest, and the open faucet relieves pressure.
  3. Check other faucets. If several have no water, more than one section may be frozen.

Safe ways to warm the pipe

  • An electric hair dryer, moved back and forth along the pipe
  • An electric heating pad wrapped around the pipe
  • Towels soaked in hot water and wrapped around the pipe, replaced as they cool
  • A portable space heater aimed at the area, kept well away from anything that can burn and never left unattended

Start near the faucet and work back toward the frozen section so melting water can flow out. Keep applying heat until full water pressure returns.

Keep electrical devices away from standing water. If water is pooling, do not use a hair dryer or heater there; call a plumber instead.

Pipes inside a wall

If the frozen section is inside a wall, turn up the heat in the house and point a space heater at the wall from a safe distance. Opening cabinet doors helps too. If that does not work, a plumber may need to open the wall.

When to call a plumber

  • You cannot find the frozen section or cannot reach it
  • The pipe has visible cracks, bulges or split fittings
  • Water starts leaking as it thaws
  • More than one area is frozen or the house has no water at all

If the pipe bursts

  1. Close the main water shutoff immediately.
  2. Turn off power to the affected area if water is near outlets or appliances, but only if you can reach the breaker panel without standing in water.
  3. Take photos for your insurance claim, then start removing water.

See our burst pipe repair cost guide for what the repair usually costs, and our guide on how to prevent frozen pipes to stop it from happening again.

Common questions

How long does it take to thaw a frozen pipe?

It can take anywhere from under an hour to several hours depending on how much is frozen and where. Keep heat on it until full pressure returns.

Will frozen pipes thaw on their own?

They may once temperatures rise, but a pipe can burst in the meantime. Thawing it promptly and safely is better.

Can I pour hot water down the drain to thaw pipes?

Drains and supply pipes are separate. Hot water down a drain will not thaw a frozen water supply line.

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