Pipes Frozen? What to Do Now, How to Thaw Them Safely and How to Prevent a Burst

If your pipes are frozen, open the faucet the pipe feeds, find the frozen section and warm it gently with a hair dryer, an electric heating pad or towels soaked in hot water until full pressure returns. Never use a torch or any open flame. If you cannot find or reach the frozen spot, or the pipe has already split, shut off the main water valve and call a licensed plumber.

If your pipes are frozen, what do you do? Step by step

These steps follow American Red Cross guidance on thawing frozen pipes. Take them in order:

1. Check for a leak first. Look along the pipe for splits, bulges, wet drywall or dripping. If you see any, shut off the main water before thawing, or the pipe will start spraying water as soon as the ice melts.
2. Open the faucet. Turn on both hot and cold at the fixture the frozen pipe feeds. An open faucet relieves pressure, and moving water helps melt the rest of the ice.
3. Find the frozen section. See the next section for where to look.
4. Apply gentle heat, starting near the faucet and working back toward the frozen spot, so melted water has somewhere to go. A hair dryer, an electric heating pad wrapped around the pipe, a space heater kept away from anything flammable, or towels soaked in hot water all work.
5. Keep heating until full water pressure returns. A trickle means there is still ice in the line.
6. Check every other faucet in the house. If one pipe froze, others may have too.
7. Watch the thawed section for an hour or two. Small cracks often show up only once water is flowing under full pressure.

Signs your pipes are frozen

• No water or only a trickle from one faucet while others work normally. This is the classic sign of a frozen pipe.
• No water anywhere in the house on a very cold morning. That usually means the main service line is frozen where it enters the house or runs through a crawl space.
• Frost on exposed pipes, or pipe that is ice-cold and hard to the touch.
• A toilet that will not refill after flushing.
• Bulging or split pipe, or new damp spots on walls or ceilings, which mean the pipe may already have burst.

How to find the frozen section

Pipes that freeze most often are the ones exposed to outside air: outdoor hose bibs, supply lines in unheated crawl spaces, attics, garages and basements, pipes under kitchen and bathroom sinks on outside walls, and pipes running through poorly insulated exterior walls. If only one fixture is affected, follow its supply line back toward the nearest cold area. If the whole house is dry, check where the water service comes through the foundation. Feel along accessible pipe for the coldest spot or look for frost.

If the frozen section is inside a finished wall or ceiling, do not cut into it yourself. You can raise the room temperature, open cabinet doors and aim a space heater at the wall from a safe distance. If that does not restore flow within a few hours, call a plumber.

What temperature do pipes freeze?

Water freezes at 32°F, but pipes inside a house usually do not freeze the moment the outdoor temperature drops below that. The commonly cited "temperature alert threshold" is 20°F outdoors. It comes from research by the University of Illinois Building Research Council, summarized by the Institute for Business & Home Safety (IBHS). In field tests, uninsulated pipes in an unheated attic began freezing once the outdoor temperature fell to about 20°F, and a survey of plumbers in southern states found burst-pipe calls started when temperatures dropped into the teens.

Two things explain why the threshold is well below 32°F:

• Unheated parts of a house stay a few degrees warmer than outdoors. An insulated attic might be 37–38°F when it is 32°F outside.
• Water supercools. It drops several degrees below 32°F before ice starts to form.

Treat 20°F as a warning, not a guarantee. The research was aimed at homes in milder climates, and the pipe's surroundings matter more than the forecast. A pipe hit by wind through a crack in the foundation, or one that runs along an uninsulated outside wall, can freeze at higher outdoor temperatures. Length of the cold spell matters too. A long stretch of below-freezing days is riskier than a single cold night.

Can pipes freeze above 32 degrees?

The water itself has to reach 32°F or lower to freeze. But the temperature on your phone is not the temperature at the pipe. On a clear, still night, surfaces exposed to the sky can lose heat faster than the surrounding air, and drafty crawl spaces or garages can sit below the forecast low. So a reported low of 33–35°F is not a promise that an exposed outdoor pipe or hose bib is safe.

What happens when your pipes freeze

Water expands about 9% when it freezes. Surprisingly, the pipe usually does not burst where the ice is. As ice forms, it pushes water toward the closed faucet. Pressure builds in that trapped stretch of pipe between the ice and the faucet until the pipe or a fitting gives way. That is why a dripping or open faucet helps: it gives the pressure somewhere to go. It is also why many bursts are found only after the thaw, when water suddenly pours through the split.

Copper and steel split. PEX tubing is more forgiving, but its fittings and connections can still fail. Do not assume plastic plumbing is immune.

What to do if a frozen pipe bursts

1. Shut off the main water valve. It is usually where the service line enters the house: in the basement or crawl space, in a utility room, near the water heater or in a garage. In mild climates it may be outside. Some homes also have a curb-stop valve at the street. Find yours before winter and make sure it turns.
2. Deal with electricity. If water is near outlets, fixtures or the panel, switch off the affected circuits only if you can reach the breaker while standing somewhere dry. Otherwise call the utility or an electrician. Never walk into standing water when the power might be on.
3. Open faucets to drain the lines, and turn off the water heater according to the manufacturer's instructions if the system will be drained.
4. Document everything with photos and video before cleanup, then move belongings out of the wet area.
5. Start drying within 24–48 hours to limit mold. Our guides to the water damage restoration process and the first 24 hours explain what proper drying involves. If water came through a ceiling, see ceiling water damage. If it pooled downstairs, see flooded basement.

Typical costs

These figures, from HomeAdvisor's 2026 cost data, cover only the plumbing. Drying, drywall, flooring and possible mold work are separate and usually cost far more. Our free water damage cost estimator can give you a rough figure, and mold remediation cost covers the worst case.

How to keep pipes from freezing

In a home you live in

• Insulate exposed pipes in crawl spaces, attics, garages and under sinks with foam or fiberglass sleeves.
• Disconnect, drain and store garden hoses. Close the indoor shut-off valves to outdoor faucets and leave the outside faucet open to drain.
• During cold snaps, open sink cabinet doors on exterior walls, keep the garage door closed and let a faucet on a vulnerable line drip.
• Keep the thermostat at the same setting day and night during extreme cold. Skip the overnight setback.
• Use only UL-listed heat tape or heat cable with a built-in thermostat, installed according to the manufacturer's instructions.
• Seal drafts around foundation vents, rim joists and where pipes pass through outside walls.

In a vacant cabin or second home

Second homes are where frozen pipes do the most damage, because a burst can run for days before anyone notices. That is a real risk in mountain areas like Lake Tahoe, where homes can sit empty through long freezes.

• Leave the heat on. The Red Cross recommends setting the thermostat no lower than 55°F when you are away. The Insurance Information Institute suggests about 65°F during severe winter storms. Have a backup plan for power outages.
• Winterize if the home will sit empty for long. Shut off the main valve, drain the supply lines and water heater, and if the heat will be off, have a plumber blow out the lines and, where they recommend it, put non-toxic antifreeze in drain traps. Do not pour antifreeze into supply lines yourself.
• Add remote monitoring. Wi-Fi leak sensors, a smart thermostat with low-temperature alerts and an automatic water shut-off valve are inexpensive compared with one burst pipe.
• Arrange check-ins. Have a neighbor or property manager visit after every hard freeze or power outage, and give them the shut-off location.

Does insurance cover frozen pipes?

Standard homeowners policies generally cover sudden and accidental water damage from a pipe that freezes and bursts. Coverage usually depends on reasonable care. Many policies exclude freeze damage if you did not keep the heat on or did not shut off the water and drain the plumbing. Homes left vacant or unoccupied face extra conditions, and some policies limit coverage after a set number of consecutive vacant days. Read your policy before you leave a cabin empty for the season. "Water damage and freezing" is one of the most common and expensive claim categories. Insurance Information Institute data shows about 1 in 60 insured homes has such a claim each year, averaging about $14,000 per claim in 2018–2022.

For more, read does homeowners insurance cover water damage and our insurance restoration claims guide. If you need a drying company, get quotes from licensed local contractors. Our tips on choosing a restoration contractor can help. If your roof is also icing up, see our guide to ice dams.

Sources

• American Red Cross: Preventing and Thawing Frozen Pipes
• IBHS / International Code Council: Freezing and Bursting Pipes (University of Illinois Building Research Council findings)
• Insurance Information Institute: Mitigation reduces winter weather risks for homes
• Insurance Information Institute: Facts and statistics, homeowners and renters insurance
• HomeAdvisor: Burst pipe repair cost (2026 data)

Frequently asked questions

If my pipes are frozen, what do I do first?

Check the pipe for cracks or leaks, and shut off the main water valve if you find any. Then open the faucet the pipe feeds and warm the frozen section gently with a hair dryer, heating pad or hot towels, working back from the faucet. Never use an open flame. If you cannot reach the frozen spot, call a licensed plumber.

What temperature do pipes freeze?

Water freezes at 32°F, but pipes inside a home usually start freezing when outdoor temperatures fall to about 20°F. That alert threshold comes from University of Illinois Building Research Council tests on uninsulated attic pipes. Exposed or drafty pipes can freeze at higher temperatures, especially during long cold spells.

Can pipes freeze above 32 degrees?

The water must reach 32°F or colder to freeze. However, the forecast air temperature is not the temperature at the pipe. Drafty crawl spaces, exposed hose bibs and surfaces cooling under a clear night sky can drop below the reported low, so pipes can freeze on nights when the forecast says 33 to 35°F.

Why do I have no water but the pipes are not burst?

If no water comes out anywhere in the house on a very cold day, the main service line is likely frozen where it enters the home or runs through a crawl space. If only one faucet is dry, that branch line is frozen. Keep faucets open, warm the suspected section gently and call a plumber if flow does not return.

How long does it take for pipes to freeze?

It depends on how exposed the pipe is, the temperature and the wind. Uninsulated pipes in unheated spaces can freeze after a few hours of sustained temperatures in the low 20s or below, while protected interior pipes may take much longer. Long cold spells are riskier than a single cold night.

Does homeowners insurance cover burst frozen pipes?

Usually, if the burst was sudden and accidental and you took reasonable care, such as keeping the heat on or shutting off and draining the water. Claims are often denied when a home was left unheated or vacant without those precautions. Check your policy for vacancy conditions before leaving a second home empty for the winter.