# Frozen pipes: prevent them, thaw them, and what to do if one bursts

Updated: 2026-10-24 · https://pros411.com/en/guides/plumbers/frozen-pipes

## Short answer

If you have a frozen pipe, open the faucet it feeds and leave it open. Warm the pipe gently with a hair dryer or heating pad, starting near the faucet. Never use a torch or open flame. If a pipe bursts, shut off the main water valve right away and call a plumber. To prevent it, drip faucets on outside walls, open sink cabinets and keep the heat at 55°F or more.

> Safety first: Never thaw a pipe with a torch, a lighter or a propane heater: it can start a fire or make the pipe burst. Never run a gas generator or a grill indoors or in the garage to stay warm: the fumes can kill.

## How to thaw a frozen pipe safely

![Cartoon kitchen faucet shivering, with a frozen pipe and icicles under the sink and snow outside](https://pros411.com/img/guias/frozen-pipes.webp)

1. **No water? Leave the faucet open.** If the faucet only coughs air on a freezing day, a pipe froze. Leave it open: as the ice melts, the water needs a way out.
2. **Open the cabinet doors.** That lets warm air from the house reach the pipes under the sink. Look for the part of the pipe with frost on it, usually along an outside wall.
3. **Warm it from the faucet side, never with a flame.** Use a hair dryer or a heating pad. Start near the faucet and move toward the ice. Never use a torch, a lighter or anything with a flame.
4. **Keep going until the water flows.** First a trickle, then full pressure. Keep warming until it runs normally, then check the other faucets in the house.
5. **Check for leaks. Burst? Shut off the main.** Look under the sink for drips or a split pipe. If it burst, shut off the main water valve right away and call a plumber.

## Before the freeze

1. Find your main water shut-off valve now and make sure it turns. It is often where the line enters the house, in the garage, or in a box near the street.
2. Disconnect garden hoses and cover outdoor faucets with an insulated cover.
3. Let a thin stream drip from faucets on exterior walls, both hot and cold.
4. Open the cabinet doors under kitchen and bathroom sinks so warm air reaches the pipes.
5. Keep the thermostat at 55°F or more, day and night, even if you leave home.
6. Wrap pipes in unheated spaces (attic, garage, crawl space) with foam pipe insulation.

## If a pipe burst

1. Shut off the main water valve immediately.
2. If water is near outlets, appliances or the electrical panel, turn off the power at the panel. Do it only if you can get there on a dry floor. If not, stay away and call the power company.
3. Open the faucets to let out the water left in the pipes.
4. Move furniture and valuables, pick up the water, and take photos and video for your insurance.
5. Call a plumber to fix the pipe. If water soaked walls or floors, also call a water damage company to dry them out.

## When to call a plumber

- A pipe burst or you see water coming from a wall or ceiling.
- No water comes out of several faucets and you cannot find the frozen part.
- The frozen pipe is inside a wall, under the slab or in a place you cannot reach safely.
- Water heater or sprinkler lines froze.

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## Frequently asked questions

### At what temperature do pipes freeze?

Pipes are at risk when it stays below about 20°F for several hours, especially in attics, garages and outside walls. In warm states like Texas, pipes are often less insulated, so a few hours below freezing can be enough.

### Should I drip faucets during a freeze?

Yes, on faucets connected to pipes along exterior walls or in unheated spaces. Moving water is less likely to freeze, and dripping relieves pressure if a section starts to freeze.

### Will a frozen pipe burst?

Not always, but it can. Pressure builds between the ice and the closed faucet, which is why opening the faucet before thawing helps. After it thaws, check the pipe for drips or bulges.

### Is a burst pipe an emergency?

Yes. Shut off the main water valve and call. Use the "24/7 emergencies" filter to find plumbers who answer now; after a big freeze they get busy fast.

### Can I use a hair dryer to thaw a frozen pipe?

Yes. Start near the faucet, keep it moving along the pipe and never leave it on alone or near water on the floor. A heating pad or towels soaked in hot water also work.

### How do I find a frozen pipe?

Check which faucets have no water and follow their pipes. The frozen part is usually along an outside wall, in the garage, the attic or a crawl space. If it is inside a wall or you cannot reach it, call a plumber.