A frozen pipe needs slow, gentle, even heat applied along its length — nothing more aggressive than that. The goal is to thaw the ice gradually so pressure can release safely as it melts. Rushing this with an open flame or excessive heat is exactly how a simply frozen pipe becomes a burst one.
A blowtorch, propane torch, or any open flame near a pipe — especially inside a wall or a confined space — is a serious fire risk and can also cause the pipe itself to fail suddenly from uneven heating. This applies to both metal and plastic pipes.
Before you start
Turn off the main water supply before you begin thawing. If the pipe has already cracked from the ice expanding inside it — which happens more often than people expect — you want the system empty and the water off before that crack starts leaking the moment it thaws.
Finding the frozen section
Turn on the affected tap first. No water, or just a trickle, confirms a freeze somewhere between that tap and the main supply. Frozen sections are most often in unheated or exposed areas: pipes running along an exterior wall, in an unheated basement, crawl space, attic, or garage. Look for a section of pipe that is noticeably colder to the touch, or that shows frost or a slight bulge.
How to thaw it safely
- Keep the tap open
Leave the affected tap open slightly throughout the thawing process. This lets water start flowing the moment the ice begins to clear, and relieves pressure gradually rather than all at once.
- Apply gentle, even heat
A hair dryer on a low-to-medium setting, an electric heating pad wrapped around the pipe, or towels soaked in hot water are all safe options. Work from the tap end of the frozen section back toward the blockage, not the other way round.
- Be patient
Thawing can take anywhere from a few minutes to a couple of hours depending on how long the section is and how solidly frozen it is. Keep applying gentle heat until water flow returns to normal.
- Check for damage as it thaws
Watch closely as the ice clears for any sign of a split or crack in the pipe — this is common with a hard freeze and is exactly why the main supply should stay off until you have confirmed the pipe is intact.
- Check other cold-prone pipes too
If one pipe froze, others in similarly exposed locations may have as well, even if they are not showing symptoms yet. Check taps around the house.
Preventing it next time
- Insulate exposed pipe sections in unheated areas — foam pipe sleeves are inexpensive and simple to fit.
- During severe cold snaps, let affected taps drip slightly overnight — moving water is far less likely to freeze solid.
- Keep cabinet doors under sinks on exterior walls open during cold weather to let household heat reach the pipes.
- Know where your main shut-off valve is before you need it in an emergency.
When to call a plumber
Call a plumber immediately if you find a split or cracked pipe during thawing, if you cannot locate the frozen section, or if the pipe is in a wall cavity or other spot you cannot safely reach and apply heat to yourself.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
