Frozen pipe burst — now what? The 10-minute drill before the water bill doubles
A frozen pipe usually doesn't split while frozen — it splits when it thaws, at the crack the ice made. Here's the order of operations that saves the house.
In the next 10 minutes you'll stop the pressure, save the drywall, and know whether this is a $400 thaw or a $2,000 wall repair.
The steps below are what plumbers wish every homeowner knew before the freeze, not after. When you need someone tonight, we email vetted local plumbers for free.
The first 10 minutes — do these in order
- Kill the main water supply. Where the line enters the house (basement wall, crawlspace, or the street-side box — key needed, turn left). If you don't know where it is, find it RIGHT NOW and photograph it. This one move is the difference between a puddle and a ceiling collapse.
- Open the affected faucet. Relieves trapped pressure — the thing that actually bursts the pipe when thawing starts. Just a crack open.
- Cut power to the area if water is near outlets, the water heater, or running along baseboards.
- Start catching and documenting. Towels + a bucket, then your phone: wide shot of the room, close-up of the wet wall/ceiling with a date written on painter's tape. The claim-proof checklist explains why the tape matters for insurance (it does).
- Begin drying within the hour. Wet drywall starts feeding mold at ~48 hours; wet carpet at ~24. Fans now, dehumidifier if you own one. See the full drying clock.
Is it frozen — or already burst?
| What you see | What it means |
|---|---|
| Faucet gives a dribble then stops, weather is freezing | Frozen, not burst yet. Time to thaw carefully (below). |
| Faucet wide open, nothing comes out | Likely a frozen main line or a burst upstream — call a plumber today. |
| Water flowing but wall/ceiling damp or bulging | Burst inside the wall. Shutoff, then extraction + plumber — every hour adds drying days. |
| Bulging stripe on pipe under sink, no leak yet | Pipe about to fail. Do not thaw it yourself — plumber visit before it becomes a flood. |
| Drip after a thaw | A crack. One more freeze-thaw cycle from bursting. Get it fixed this week. |
How to thaw without cracking the pipe
Start at the faucet end and work backward — the melt needs somewhere to escape. Hair dryer on medium, a heat lamp on a tripod, or a towel soaked in hot water wrapped around the pipe. Keep the faucet cracked open so you see the moment water flows. Never use a propane torch on copper (the joints fail) and never on PVC (it melts and delaminates). If the frozen section is inside a wall, in a crawl space you can't reach, or the whole house is dry — stop; that's a plumber's $400–$800 thawing job, not a DIY.
What it costs after the thaw
Exposed pipe fixes run $150–$500; a burst inside a finished wall runs $800–$2,100 with the drywall patch — and if water had an hour to travel, drying adds more. Full range table with wall-access variables: burst & frozen pipe repair cost →
Insurance: you're holding the friendliest claim there is
Burst/frozen pipes are covered on standard HO-3 policies when the failure is sudden — which yours is. Two traps: nobody says "gradual" out loud before the adjuster arrives, and nobody photographs before demo. The exact wording and photo order: insurance guide → and the free 2-page checklist.
Frozen line or burst tonight?
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