A frozen pipe is not the expensive part. The expensive part is what happens when the ice expands, splits the pipe, and then thaws. Water runs inside the wall until someone notices.
Pipes freeze where cold air reaches them: in outside walls, under sinks on outside walls, in crawl spaces, unheated garages and attics, and at outdoor faucets. A few cheap steps before the first hard freeze cover almost all of it.
Before a cold snap
- Find the main water shutoff and make sure it turns. If a pipe bursts, this is the one thing you need to know.
- Disconnect garden hoses and shut off and drain outdoor faucets. Water left in a hose bib can freeze and split the pipe inside the wall.
- Insulate pipes in crawl spaces, garages and attics with foam pipe sleeves from any hardware store.
- Seal drafts near pipes: gaps where pipes or cables pass through outside walls let freezing air straight onto them.
- Keep the heat at 55°F or higher, even when you are away.
- On the coldest nights, open the cabinet doors under sinks on outside walls, and let a faucet on an outside wall drip. Moving water is much harder to freeze.
If a pipe freezes
The sign is a faucet that gives a trickle or nothing on a cold morning while others work. Leave that faucet open, so melting water has somewhere to go.
Warm the pipe gently: a hair dryer, a space heater kept well away from anything that burns, or towels soaked in warm water. Start near the faucet and work back toward the frozen part.
Never use an open flame, a torch or a propane heater on a pipe. It is a fire risk, and heating one spot too fast can burst it.
If you cannot reach the frozen section, or it does not thaw in about half an hour, call a plumber.
If a pipe bursts
- Shut off the main water valve right away.
- If water is near outlets, the panel or anything electrical, turn off power to that area at the breaker, and only if you can reach the panel without standing in water.
- Open faucets to drain the lines, and move what you can out of the water.
- Take photos for insurance before you clean up.
- Call a plumber for the pipe, and a water damage company if water got into walls, ceilings or flooring.
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Start a requestCommon questions
At what temperature do pipes freeze?+
Pipes in unheated or outside-wall spaces are at risk once outside temperatures fall to about 20°F, sooner with wind or long cold spells.
Should I let faucets drip?+
On the coldest nights, a slow drip from a faucet on an outside wall helps. Moving water is much harder to freeze, and an open faucet relieves pressure if ice forms.
Can I thaw a pipe with a torch?+
No. Open flames are a fire risk and can heat one spot fast enough to burst the pipe. Use a hair dryer, a space heater at a safe distance, or warm towels.