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Frozen pipes: how to thaw them safely

When water stops coming out of a faucet in freezing weather, a pipe may be frozen. This page helps you find the frozen section, thaw it gently, and avoid a burst pipe.

Do this now

  1. Leave the faucet open. Water will start to flow as the ice melts, and the moving water helps melt more ice.
  2. Look for pipes that are frosty, bulging, or cracked, and for any sign of leaking water.
  3. If a pipe has burst or is leaking, close the main water shutoff first. Our burst pipe guide explains how.
  4. Warm the frozen section slowly, starting at the faucet end and working back toward the frozen part.
  5. Keep heating until full water pressure returns, then check the other faucets in the house.

Find the frozen section

Frozen pipes are most common in places the cold reaches: outside walls, unheated basements, crawl spaces, attics, garages, and under kitchen and bathroom sinks. If only one faucet is dry, the freeze is probably in the pipe leading to it. If every faucet is dry, the freeze may be near the main line or the meter.

Look and feel along the pipe for a section that is frosty or very cold. A pipe may also be bulging. If you can hear nothing when you open the faucet, or only a trickle, the ice is still blocking the flow.

Thaw the pipe

Use gentle heat. Rapid heating can crack a pipe or make steam that bursts it.

  • An electric hair dryer, held a hand's width from the pipe and moved back and forth
  • Towels soaked in hot (not boiling) water, wrapped around the pipe and refreshed as they cool
  • An electric heating pad wrapped around the pipe
  • A portable electric heater, set up safely and well away from anything that can burn

Keep electric cords and devices away from any standing water. Do not leave a heat source alone, and never use one while you are standing in water.

... danger "Never use an open flame" Do not use a blowtorch, a propane or kerosene heater, a charcoal stove, a lighter, or any other open flame on a pipe. It can start a fire inside a wall and can poison you with carbon monoxide. See carbon monoxide.

Check other pipes

If one pipe froze, others may be frozen as well. Open every faucet and see which ones run slowly or not at all. Check for wet walls, ceilings, or floors, which can point to a crack you cannot see.

When to call a plumber

Call a licensed plumber if:

  • You cannot find the frozen area
  • The frozen pipe is inside a wall, under a floor, or somewhere you cannot reach
  • You have tried to thaw the pipe and it is still frozen
  • A pipe is cracked or leaking, or water is coming through a ceiling or wall
  • The freeze is at the main line, the water meter, or outside the house

If water is spreading, close the main shutoff and call. If the water is near outlets or the electrical panel, keep away and read the electricity advice in our burst pipe guide.

... warning "A thawed pipe may leak" A pipe that froze can crack, and the crack may only show once the ice melts. After thawing, watch the pipe for leaks. If water appears, close the main shutoff.

If a pipe bursts after thawing

Close the main water shutoff right away. Open the faucets to drain the system. Move belongings out of the wet area, take photos for your insurer, and call a plumber. Contact your insurer soon, since many policies cover sudden burst pipe damage but not damage from long neglect.

Stop pipes from freezing again

When a cold snap is forecast:

  • Open cabinet doors under sinks on outside walls so warm air reaches the pipes
  • Let a faucet drip slowly overnight, since moving water is less likely to freeze
  • Keep your home heated, even if you are away
  • Disconnect garden hoses and cover outdoor taps
  • Insulate exposed pipes in basements, crawl spaces, attics, and garages
  • Seal gaps and cracks where cold air enters, especially near pipes

Learn where your main water shutoff is before winter, and show everyone in your home. If you plan to leave a home empty for a long time in winter, ask a plumber about draining the system.