Frozen Pipes: What to Do Before They Burst
No water, or just a trickle, on a freezing morning usually means a frozen pipe. Here's how to thaw it safely and catch a burst before it floods.
Signs a pipe is frozen
- A faucet only trickles, or nothing comes out, during freezing weather
- Frost on a visible pipe, often in the crawl space or under a sink
- A toilet that won't refill
- Strange smells from drains (gases can't escape past the ice)
Be ready to shut off the water. A frozen pipe may already be cracked. When the ice melts, water can spray out. Know where your main shutoff is before you start thawing.
How to thaw a frozen pipe safely
- Open the faucetTurn on the faucet the pipe feeds. Running water helps melt the ice and relieves pressure.
- Find the frozen sectionUsually where the pipe runs through a cold spot: crawl space, exterior wall or under a sink against an outside wall.
- Apply gentle heatUse a hair dryer, a space heater kept at a safe distance, warm towels or a heating pad. Start near the faucet and work back toward the frozen spot.
- Keep heating until full pressure returnsThen check every other faucet in the house. If one pipe froze, others may have too.
- Check for leaksLook and listen for drips, spraying or wet spots, especially in the crawl space, as the pipe thaws.
Never do this
- No open flames: no torches, propane heaters or lighters. It's a serious fire risk, and boiling water can make the pipe explode.
- Don't leave space heaters unattended or near anything flammable.
- Don't use electrical devices while standing in water.
Call for help if
- You can't find or reach the frozen section (inside a wall or ceiling)
- The pipe has visibly cracked or bulged
- Water is leaking once it thaws
- Water reached floors, walls or the crawl space. That needs drying, not just a plumbing repair.
If it burst, shut off the main water valve right away and see burst pipe cleanup or the emergency checklist.
Frequently asked questions
How long does it take a frozen pipe to burst?
It varies. Some pipes split within hours of freezing; others hold until they thaw. Many bursts are only discovered when temperatures rise and water starts flowing through the crack.
Will frozen pipes thaw on their own?
Often, once temperatures rise. But if a pipe cracked while frozen, it will leak as it thaws, so watch closely and know where your shutoff is.
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