Signs a Frozen Pipe Is About To Burst
Reduced or no flow at one fixture during a freeze is the first sign. Visible frost on a pipe, a bulge or a change in the metal's shape, and unusual sounds when the water is on are the others. Shut the main before investigating any of them.
What to do right now
Do these first. None of them need tools or plumbing knowledge, and they limit what this ends up costing you.
- Shut the main firstBefore you touch or thaw anything. If the pipe has already split, thawing it with the water on means it starts flowing unattended.
- Look for frost and shape changesFrost on the outside of a pipe means it is at or below freezing inside. A bulge, a change in diameter or a section that looks stretched means the ice has already deformed the metal.
- Listen when the water is onBanging, knocking or an unusual hiss when a tap is opened during a freeze suggests a partial blockage or a compromised section.
Does this need a plumber tonight?
- A pipe that has visibly bulged or deformed
- Reduced or no flow at a fixture during a freeze
- Any sign of moisture around a frozen section
- No water at all while the house is below freezing
- Frost on an outside line you have already isolated and drained
- Slight reduction in flow that recovered on its own
Why the split does not leak straight away
Because the ice that split the pipe is also sealing it. The failure only becomes visible when it thaws, which is usually a day or two later on the first warm afternoon.
This is why a frozen pipe warrants attention even when nothing is leaking. The damage may already be done and simply waiting for the temperature to rise.
It is also why restoring flow is not the end of the job. Reopen the water slowly and watch the pipe while the system refills, because that is when a split announces itself.
- Reduced or absent flow at one fixture during cold weather
- Visible frost on the pipe surface
- A bulge or a change in the pipe's diameter
- Banging or unusual noises when the water is on
- A pipe that feels noticeably colder than its neighbours
What to do with the warning
Shut the main, thaw gradually with the affected tap open, then reopen the water slowly and watch the section while it fills.
If you find a bulge or deformation, do not thaw it and hope. That pipe has already been damaged and should be replaced rather than returned to service.
Never use an open flame or a blowtorch, at any stage. It is the leading cause of house fires during a cold snap in Northern Utah.
Questions people ask about this
My pipe is frozen but not leaking. Am I lucky?
Possibly, or possibly the ice is holding a split closed. Shut the main before thawing and watch the section carefully when the water comes back on.
Should I thaw it or wait?
Thaw it, gradually, with the main shut. Waiting for a natural thaw means the split reveals itself when nobody is watching.
There is a bulge in the pipe.
That pipe is compromised and should be replaced rather than thawed and reused. The metal has already been stretched past where it can be trusted.
If that is not quite what you have
Not sure how urgent this is?
Describe what you can see and hear. We will tell you whether it needs someone tonight, and what to do in the meantime either way.
Or send it over
Four things and a photo.