How to Prevent Frozen Pipes from Bursting (2026): A Homeowner’s Plan

Quick guide: Short answer Why pipes burst Before winter During a freeze Leaving home If a pipe freezes FAQs

The short answer

Preventing a burst pipe is mostly about three things:

Keep vulnerable pipes above freezing — insulation, heat, and blocking cold air infiltration.
Relieve pressure — a dripping faucet on at-risk lines.
Limit the damage if it happens anyway — know where the main shutoff is, and consider an automatic one.

Do these before the first hard freeze: disconnect and drain garden hoses, shut off and drain outdoor spigots, insulate pipes in unheated spaces, seal air leaks near pipes, and locate and test your main water shutoff valve.

Best for: Homeowners in any climate that sees temperatures below freezing, including regions where hard freezes are rare — those homes are often the least prepared and take the most damage.

Avoid: Setting the thermostat low or off while away in winter, and using open flame to thaw a pipe.

For automatic shutoff devices that limit damage when prevention fails, see: Compare our smart water shutoff picks.

Why pipes burst (it is not where you think)

The intuitive explanation — ice expands and splits the pipe at the ice — is usually wrong. What actually happens:

Water freezes at a cold spot, forming an ice plug.
The plug grows and blocks the pipe.
Water continues to freeze behind the plug, and the expanding ice pushes water toward the closed faucet.
Pressure builds in the trapped section between the ice plug and the closed faucet.
The pipe fails at the weakest point in that pressurized section — often well away from the ice itself.

This is why opening a faucet is the single most effective free action during a freeze. It gives the pressure somewhere to go. Even if the pipe freezes, it may not burst.

The damage happens on the thaw. A pipe can split while frozen and leak nothing, because ice is plugging the crack. When it thaws, water pours out — frequently while nobody is home to notice.

Before winter: the fall checklist

Outside:

Disconnect, drain, and store garden hoses. A connected hose traps water in the spigot and is a leading cause of burst outdoor lines.
Shut off the interior valve for each outdoor spigot, then open the spigot to drain the line.
Install insulated faucet covers on hose bibs.
Blow out or drain irrigation systems and pool lines.
Seal exterior wall penetrations where pipes enter, and close foundation vents in freezing weather if your crawlspace design allows it.

Inside:

Insulate pipes in unheated spaces — crawlspaces, attics, garages, basements, and any run against an exterior wall. Foam sleeves are inexpensive and take an afternoon.
Seal air leaks near pipes with caulk or spray foam. Wind blowing through a rim joist or a sill plate gap will freeze a pipe that insulation alone would have protected.
Add heat tape or heat cable on the highest-risk runs. Use a UL-listed product rated for your pipe material, follow the instructions exactly, and never overlap the cable on itself — improper installation is a fire hazard.
Locate and exercise the main shutoff valve. Turn it fully off and back on once a year so it does not seize. If it will not close, replace it — a seized main valve during a burst is the worst possible discovery.
Insulate the water heater and its supply lines if it lives in an unheated space.
Know your plumbing. Walk the house and note where pipes run through cold spaces. That is your at-risk list.

Consider adding: point leak sensors under sinks, behind the washing machine, at the water heater, and near any pipe in a cold space. They cost very little and they call you. Our room-by-room placement guide covers where they earn their keep.

During a hard freeze

When a sustained cold snap is forecast, particularly at or below roughly 20 °F:

Open cabinet doors under kitchen and bathroom sinks on exterior walls so room heat reaches the pipes. Move household chemicals out of reach of children and pets first.
Drip the at-risk faucets. A slow steady trickle, on both hot and cold sides. Prioritize the fixture furthest from where the water enters the house and any fixture on an exterior wall.
Keep the thermostat at a consistent temperature day and night. Setback schedules save a little on heating and cost a great deal if a pipe bursts. A minimum of 55 °F is the commonly cited floor.
Open interior doors so heat circulates, including to rooms you normally keep closed.
Keep the garage door closed if there is plumbing in the garage or in the wall behind it.
Do not use a space heater unattended in a crawlspace or near combustibles. Heating equipment is a leading cause of winter home fires.
Check on vacant properties — a rental between tenants, a house on the market, or a second home.

Leaving home in winter

This is where the expensive failures happen, because nobody notices for days.

Never turn the heat off. Set it no lower than 55 °F, and use a smart thermostat that alerts on low indoor temperature.
Shut off the water at the main and drain the lines if you will be gone for an extended period. A house with no water in the pipes cannot flood.
If you cannot drain, at minimum shut off the water heater's supply and consider shutting the main.
Have someone check the house every few days, and make sure they know where the main shutoff is and how to use it.
Install a smart water shutoff or at least freeze-alert sensors. Remote shutoff is exactly the scenario these devices are built for — our vacation home guide covers the setup.
Check your insurance policy. Some policies limit or exclude coverage for freeze damage in a home that was left unheated or where the water was not shut off. Read the actual language before you need it.

If a pipe freezes: what to do

You will know because a faucet produces only a trickle or nothing at all while others work, or you see frost or bulging on an exposed pipe.

Open the faucet served by that pipe, both hot and cold. This relieves pressure and gives meltwater somewhere to go.
Locate the frozen section. Follow the line from the faucet toward where it passes through a cold space.
Apply gentle heat starting at the faucet end and working toward the frozen section. A hair dryer, a heating pad wrapped around the pipe, a portable space heater aimed at the area, or towels soaked in hot water.
Never use an open flame. No propane torch, no kerosene or propane heater, no charcoal. Thawing pipes with open flame causes house fires every winter, and it can also boil water inside a closed section and rupture the pipe.
Keep applying heat until full pressure returns. Then check the entire run for leaks — a split may only reveal itself once the ice melts.
Check other faucets. If one pipe froze, others in similar locations may have too.
If you cannot locate it, cannot reach it, or the pipe has burst — shut off the water at the main and call a plumber.

If a pipe has already burst: shut off the water at the main immediately, shut off electricity to affected areas at the breaker if water is near outlets or fixtures, document everything with photos and video before cleanup, and call your insurer. Fast water extraction and drying is what prevents a water claim from becoming a mold claim.

Common mistakes to avoid

Turning the heat down while away. The savings are trivial next to the risk.
Leaving hoses connected through the first freeze.
Not knowing where the main shutoff is. Everyone in the household should know, and it should turn.
Insulating a pipe but not sealing the air leak beside it. Moving cold air defeats insulation.
Using a torch to thaw. The single most dangerous item on this page.
Assuming a warm climate is safe. Homes in mild regions often have pipes in attics and unconditioned spaces with no insulation at all, which is why rare freezes there cause so much damage.
Ignoring the thaw. The burst usually reveals itself when the ice melts, not when it forms.

FAQs

At what temperature do pipes freeze?

Water freezes at 32°F, but pipes inside a structure have some thermal buffer. A commonly cited threshold for concern is a sustained outdoor temperature at or below about 20°F, and pipes in unheated or exterior-wall locations can freeze well above that if wind is driving cold into a cavity.

Should I let faucets drip in a freeze?

Yes, on the faucets served by pipes most at risk — typically those on exterior walls or in unheated spaces. A slow trickle relieves the pressure that actually bursts pipes and keeps water moving. Drip both hot and cold sides, because both lines can freeze.

Which pipes freeze first?

Pipes in unheated spaces — attics, crawlspaces, garages, basements, and exterior walls — and any outdoor hose bib or irrigation line. Pipes running through an exterior wall cavity are especially vulnerable because insulation is often on the wrong side of them.

How do I thaw a frozen pipe safely?

Open the faucet first so melting water can escape, then apply gentle heat with a hair dryer, a heating pad, or towels soaked in hot water, working from the faucet end toward the frozen section. Never use an open flame, a propane torch, or a kerosene heater — this is a leading cause of house fires during cold snaps.

Can a smart water shutoff prevent a frozen pipe burst?

It cannot stop the pipe from freezing, but it dramatically limits the damage. A freeze alert lets you act, and remote shutoff means a pipe that bursts while you are away releases what is in the lines rather than running for days.

Bottom line

Insulate the vulnerable pipes, open cabinet doors, drip the at-risk faucets, know where your main shutoff is, and never leave a house unheated in winter without draining or monitoring it. For model-by-model comparisons and current pricing, use our main guide: Compare our smart water shutoff picks.