Originally published December 29, 2022 | Updated September 15, 2026
Frozen pipes are one of those winter problems homeowners don’t want to think about until it’s too late.
A pipe can freeze quietly inside an exterior wall, crawl space, garage, attic, basement, or under a kitchen sink. If the water inside freezes and expands, it can put tremendous pressure on the pipe. When the ice begins to thaw, a damaged pipe can suddenly leak or burst, potentially causing significant water damage.
The good news is that many frozen-pipe problems can be prevented with some preparation before freezing weather arrives.
Fall is the perfect time to identify vulnerable plumbing, insulate exposed pipes, disconnect outdoor hoses, protect exterior faucets, and make sure you know where your home’s main water shutoff valve is located.
And if a pipe does freeze, knowing what to do — and what not to do — can help prevent a small problem from becoming a major plumbing emergency.
Know Where Your Main Water Shutoff Is
Before winter arrives, every homeowner should know where the home’s main water shutoff valve is located. If a frozen pipe breaks or begins leaking, shutting off the main water supply quickly can dramatically reduce the amount of water that enters your home and limit damage.
The main shutoff is usually located where the main water service enters the house, often in a basement, crawl space, utility room, garage, or near the water heater. The exact location varies by home.
Don’t wait for a plumbing emergency to find it. Locate the valve now and make sure it can be turned off. If you’re not sure which valve controls the entire house, ask a plumber to identify it for you.
If a Pipe Freezes or Bursts
If you discover water leaking from a frozen or burst pipe, turn off the home’s main water supply immediately if it is safe to do so. Then open a faucet to relieve pressure and call a plumber. If water is near electrical equipment or outlets, avoid entering the water and follow appropriate electrical safety precautions.
If you only have a suspected frozen pipe and there is no active leak, you generally don’t need to shut off the entire home’s water supply just because the pipe is frozen. Keep the faucet open while safely thawing the pipe and monitor carefully for leaks as the ice melts.
Why do water pipes freeze?
Water expands when it freezes. That expansion creates pressure inside a pipe, and if the pressure becomes great enough, the pipe can crack or rupture.
The most vulnerable plumbing is usually found in locations where temperatures can fall close to or below freezing.
Common trouble spots include:
- Exterior walls
- Unheated garages
- Crawl spaces
- Attics
- Basements
- Under kitchen and bathroom sinks
- Plumbing near poorly insulated areas
- Water lines entering the home through the foundation
- Outdoor faucets and hose bibs
- Irrigation and sprinkler lines
The American Red Cross specifically identifies pipes in unheated areas such as basements, crawl spaces, attics and garages, along with pipes running against poorly insulated exterior walls, as particularly vulnerable.
Not every frozen pipe will burst immediately. Sometimes the ice simply blocks water flow. But a damaged section can leak once the ice begins to melt, which is why frozen plumbing should always be taken seriously.
How to prevent frozen pipes before winter
The best time to protect your plumbing is before temperatures drop below freezing.
You don’t need to wait for the first freeze warning. Fall is a good time to walk through your home and identify plumbing that could be exposed to cold temperatures.
Here are the most important steps.
1. Find vulnerable pipes around your home
Start by looking for water pipes located in areas that aren’t adequately heated.
Check:
- Garages
- Crawl spaces
- Basements
- Attics
- Exterior walls
- Under sinks
- Near exterior doors
- Around foundation penetrations
- Other areas exposed to cold drafts
Don’t assume that pipes inside the house are automatically protected. A pipe inside an exterior wall, for example, can become very cold if insulation is inadequate or cold air is entering through gaps.
If you’ve had a frozen pipe in the same location before, that’s an especially important warning sign.
Don’t simply wait for it to happen again. Try to determine why the pipe froze and correct the underlying problem.
2. Insulate exposed water pipes
Pipe insulation is one of the simplest ways to help protect vulnerable plumbing.
Foam pipe sleeves are widely available and can be installed around accessible hot and cold water pipes.
Pay particular attention to pipes in:
- Garages
- Crawl spaces
- Basements
- Attics
- Exterior walls
- Other unheated areas
Insulation doesn’t make a vulnerable pipe completely immune to freezing, but it can help slow heat loss and provide additional protection.
The Red Cross recommends insulating exposed water pipes and specifically notes that pipe sleeves and other products designed for pipe insulation can be used in vulnerable areas.
If a pipe is repeatedly freezing despite insulation, however, the problem may involve a larger issue such as inadequate insulation around the building envelope, cold-air infiltration, pipe location, or insufficient heat in the area.
3. Protect pipes near exterior walls
Pipes running along exterior walls can be particularly vulnerable during extreme cold.
If a sink is located against an exterior wall, open the cabinet doors during periods of very cold weather so warmer indoor air can circulate around the plumbing.
Before doing this, move cleaning products, medications, chemicals, and anything else that could be dangerous to children or pets out of the cabinet.
You should also look for obvious drafts or gaps around the area where pipes enter walls.
Sealing unwanted air leaks can help reduce cold air reaching the plumbing.
For more information about sealing household drafts, see our guide:
How to Seal Drafty Windows and Doors Before Winter
4. Keep your garage door closed
If your garage contains water pipes, keeping the garage door closed can help protect the plumbing from freezing temperatures.
This is particularly important during periods of extreme cold.
Even if the garage isn’t heated, reducing exposure to outdoor temperatures and wind can help keep the area from becoming as cold as the outdoors.
If plumbing repeatedly freezes in your garage, consider having a plumber evaluate the situation and determine whether the pipes need additional insulation or other protection.
5. Disconnect and drain outdoor hoses
Garden hoses can contribute to freezing problems around outdoor faucets.
Before freezing weather arrives:
- Disconnect every garden hose.
- Drain the hose.
- Store it in a protected location.
- Check the faucet for leaks or damage.
- If your home has an interior shutoff valve for the outdoor faucet, close it.
- Open the exterior faucet to allow remaining water to drain when appropriate for your plumbing configuration.
Don’t assume that simply removing the hose is enough.
A hose left attached can trap water and interfere with drainage from the faucet, increasing the risk of freezing.
HelpHouse has a separate detailed guide covering this process:
How to Winterize Outdoor Faucets Before Freezing Weather
6. Know whether you have frost-free outdoor faucets
Some newer homes have frost-free or freeze-resistant hose bibs designed to shut off the water farther inside the heated portion of the home.
That design can reduce the risk of freezing, but it doesn’t make the faucet completely maintenance-free.
A frost-free faucet can still freeze if:
- The hose remains attached
- The faucet is damaged
- The installation isn’t correct
- Water cannot drain properly
- The pipe is exposed to unusually cold conditions
If you’re not sure what type of outdoor faucet you have, it’s worth finding out before winter.
7. Protect irrigation and sprinkler lines
Outdoor irrigation systems are another potential source of winter plumbing problems.
Don’t assume that disconnecting garden hoses protects an irrigation system.
Depending on the system, winterization may involve draining water from supply lines, using the system’s designated shutoff and drain procedures, or having the system professionally winterized.
Follow the manufacturer’s or installer’s recommendations for your particular irrigation system.
If you’re unsure how your system should be winterized, contact a qualified irrigation or plumbing professional before freezing weather arrives.
8. Seal cold-air leaks near plumbing
Cold air entering through gaps around plumbing penetrations can make already-vulnerable pipes even more susceptible to freezing.
Look for openings around:
- Water pipes
- Electrical conduits
- Dryer vents
- Plumbing penetrations
- Foundation openings
- Exterior walls
Small gaps can sometimes be sealed with an appropriate caulk or expanding foam product, depending on the location and materials involved.
Don’t use spray foam or other products where doing so could interfere with required ventilation, drainage, electrical clearances, or plumbing movement.
When in doubt, ask a professional.
9. Keep your home heated during extreme cold
During severe winter weather, don’t turn the thermostat way down just because you’re sleeping or leaving the house for a short period.
The American Red Cross recommends maintaining a consistent thermostat setting during extreme cold and advises keeping the heat on at no lower than 55°F when leaving home during cold weather.
This is particularly important if you have plumbing in vulnerable areas.
A lower heating bill isn’t much of a bargain if a pipe freezes and floods the house.
10. Let vulnerable faucets drip during extreme cold
During periods of exceptionally cold weather, allowing a small amount of cold water to drip from a faucet served by vulnerable plumbing can help reduce the chance of freezing.
Running water through the pipe can make it more difficult for ice to completely block the line.
This technique is particularly relevant for plumbing serving exterior walls or other exposed areas.
You don’t necessarily need every faucet in the house running. The focus should be on plumbing that is actually vulnerable to freezing.
What temperature causes pipes to freeze?
There’s no single temperature at which every household pipe will freeze.
A pipe’s vulnerability depends on factors including:
- Outdoor temperature
- How long temperatures remain below freezing
- Pipe location
- Insulation
- Exposure to cold air
- Wind and drafts
- Indoor temperature
- Pipe material
- Amount of water movement
- Condition of the home’s insulation
That’s why homeowners shouldn’t wait for a particular temperature number before taking action.
A prolonged period of freezing weather can be enough to create problems in vulnerable locations even when other parts of the home remain relatively comfortable.
What should you do if you think a pipe is frozen?
One of the first warning signs is reduced water flow.
If you turn on a faucet and only a trickle comes out — or nothing comes out at all — a frozen pipe could be the cause.
The Red Cross recommends keeping the faucet open while attempting to thaw a frozen pipe. As the ice melts, water can begin moving through the pipe again.
If you suspect a frozen pipe:
1. Leave the faucet open.
2. Try to identify where the pipe is frozen.
Check vulnerable areas such as exterior walls, under sinks, basements, crawl spaces, garages, and locations where the water line enters the house.
3. Apply gentle heat.
If the frozen section is accessible, options can include an electric heating pad, hair dryer, or towels soaked in warm water.
The goal is to gradually warm the pipe.
4. Keep watching for leaks.
As the ice melts, water pressure may return. If the pipe has cracked, water can begin leaking.
5. Shut off the main water supply if the pipe has burst.
Knowing where your home’s main water shutoff valve is located before an emergency happens can save valuable time.
6. Call a plumber if you’re unable to safely locate or thaw the frozen pipe.
Never use an open flame to thaw frozen pipes
This is extremely important.
Never use a blowtorch, propane torch, kerosene heater, charcoal grill, or other open flame to thaw a frozen water pipe.
The Red Cross specifically warns against using open-flame devices to thaw frozen pipes because they can create a fire hazard and can cause dangerous heating of the pipe.
A slow, controlled heat source is much safer.
If the pipe is inaccessible or you’re uncomfortable attempting to thaw it yourself, call a licensed plumber.
What if the pipe has already burst?
If you discover a burst pipe, shut off the home’s main water supply immediately if you can do so safely.
Then contact a licensed plumber.
Move belongings away from the water if possible and safe, and take reasonable steps to limit additional water damage.
Don’t assume that a pipe hasn’t burst simply because you don’t see water immediately. Ice can temporarily block the damaged section. Once the ice melts, water may begin flowing through the opening.
This is one reason frozen pipes deserve prompt attention.
How do you know if a frozen pipe has burst?
Possible warning signs include:
- Water appearing around a pipe
- Damp walls or ceilings
- Water stains
- Bubbling paint
- Unexpected puddles
- A sudden drop in water pressure
- Water flowing where it shouldn’t
- A pipe that is visibly cracked or split
- Water appearing as a frozen section begins to thaw
If you discover a burst pipe, shut off the main water supply and contact a plumber.
How to Prevent Frozen Pipes While You’re Away
If you’re leaving your home during cold weather, don’t shut the heat completely off.
Set the thermostat to a safe temperature and make sure someone can check on the property if you’re going to be away for an extended period.
The Red Cross recommends leaving the heat on at no lower than 55°F when away during cold weather.
It’s also worth knowing where the main water shutoff is located and making sure a trusted person knows how to access it in an emergency.
For vacation homes or properties that will be unoccupied for long periods, a plumber may recommend additional winterization steps depending on the plumbing system and local climate.
Don’t forget about your water main
Many homeowners know where the electrical panel is and where the furnace is located but have never actually located the home’s main water shutoff.
Find it before you have a plumbing emergency.
The main shutoff is commonly located where the water service enters the home, although the exact location varies.
Make sure the valve is accessible and that household members know what it does.
If a pipe bursts in the middle of the night, being able to shut off the water quickly can make a major difference in the amount of damage.
A simple frozen-pipe prevention checklist
Before winter arrives, walk through your home and check each item:
☐ Locate and test your home’s main water shutoff
☐ Locate vulnerable water pipes
☐ Insulate exposed plumbing
☐ Check pipes near exterior walls
☐ Inspect plumbing in garages and crawl spaces
☐ Check basement and attic plumbing
☐ Seal appropriate cold-air gaps around plumbing
☐ Disconnect and drain garden hoses
☐ Winterize outdoor faucets
☐ Protect irrigation lines
☐ Make sure garage doors remain closed during extreme cold
☐ Test that you can operate the shutoff
☐ Keep the home heated during extreme cold
☐ Open cabinets around vulnerable plumbing when appropriate
☐ Know which faucets serve vulnerable pipes
☐ Consider a small drip during periods of extreme cold
☐ Make arrangements to protect plumbing if you’ll be away
When should you call a plumber?
Not every frozen pipe requires an emergency plumbing visit, but there are situations where professional help is the safest choice.
Call a plumber if:
- A pipe has burst
- You find a leak as a frozen pipe thaws
- You can’t locate the frozen section
- The frozen section is inaccessible
- You cannot safely thaw the pipe
- Water pressure doesn’t return after thawing
- Pipes repeatedly freeze in the same location
- You suspect damaged plumbing
- You aren’t sure how to winterize your plumbing
- You need to modify or relocate vulnerable plumbing
- You need professional winterization for a vacation home
- You’re dealing with an irrigation or sprinkler system you don’t know how to winterize
Need help protecting your plumbing before winter?
Find a Plumber in the HelpHouse Contractor Directory.
Frequently Asked Questions
There isn’t one specific temperature that causes every pipe to freeze. Plumbing can freeze when temperatures remain below freezing for an extended period, particularly when pipes are exposed to cold air or located in poorly insulated areas. Pipes along exterior walls, in garages, crawl spaces, attics, and other unheated areas are especially vulnerable.
Keep the heat on and maintain a consistent indoor temperature. During extreme cold, consider allowing a small amount of water to drip from faucets supplied by vulnerable pipes and open appropriate sink cabinets so warmer household air can reach the plumbing.
You don’t necessarily need to leave every faucet running. During extreme cold, a small drip can help protect faucets supplied by vulnerable pipes, particularly plumbing located along exterior walls or in other exposed areas.
For a short trip, the more important step is generally keeping the home heated and protecting vulnerable plumbing. For longer absences, particularly at a vacant property, shutting off and draining portions of the plumbing may be appropriate. Because plumbing systems vary, consider asking a plumber what winterization procedure is appropriate for your home.
Yes. PEX is flexible and can tolerate freezing better than some rigid plumbing materials, but it is not freeze-proof. A PEX water line can still freeze and cause problems when exposed to sufficiently cold conditions.
A portable space heater may be appropriate in some circumstances if it is positioned safely and kept away from combustible materials, but it should never be used in a way that creates a fire hazard. For an inaccessible or difficult-to-thaw pipe, calling a plumber is safer.
A hair dryer can be used to apply gradual heat to an accessible frozen pipe. Keep electrical equipment away from standing water and use caution. Never use an open flame to thaw plumbing.
Shut off your home’s main water supply as quickly as possible and contact a licensed plumber. Then take reasonable steps to limit water damage if it is safe to do so.
Start with areas that are exposed to cold temperatures: exterior walls, garages, crawl spaces, attics, basements, under sinks, and locations where water lines enter the home.
A power outage during extreme cold can create a serious risk because the home’s heating system may stop operating. Monitor the temperature inside the home, protect vulnerable plumbing, and follow safe emergency-heating practices. If temperatures inside the home are falling significantly, take action before pipes freeze.
Protect your pipes before the first hard freeze
Frozen pipes are much easier to prevent than they are to repair after they’ve burst.
Take some time this fall to identify vulnerable plumbing, insulate exposed pipes, seal appropriate drafts, disconnect outdoor hoses, winterize exterior faucets, and make sure everyone in the household knows where the main water shutoff is located.
And don’t wait until the first freezing night to think about your plumbing.
A little preparation now can help prevent a frozen pipe from turning into a flooded basement, damaged ceiling, expensive plumbing repair, or major insurance claim later.
Need professional help winterizing your plumbing?
Find a Plumber near you through the HelpHouse Contractor Directory.
Related HelpHouse articles
These are the internal links I’d use in the finished article:
- How to Winterize Outdoor Faucets Before Freezing Weather
- How to Prepare Your Home for Colder Weather: 15 Things to Do Before Winter
- How to Seal Drafty Windows and Doors Before Winter
- Fall Home Maintenance Checklist: 25 Essential Tasks Every Homeowner Should Complete
- How to Prepare Your Furnace for Winter
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