What to Do When You Have a Frozen Pipe

November 25, 2025

Frozen Pipes: 7 Key Steps to Find, Thaw, and Prevent Burst Pipes

Frozen pipes occur when water inside a pipe drops to freezing temperature and turns to ice. The ice blocks flow, adds pressure, and creates a real risk of leaks and bursts that damage walls, floors, and belongings.

A tiny crack from a frozen pipe can release up to 250 gallons of water in a single day, which soaks building materials and increases repair costs dramatically. This guide explains how frozen pipes happen, why they burst, how to recognize early warning signs, how to thaw pipes safely, how to prevent freezing before a cold front, and when to contact a plumber for professional help.

What Is a Frozen Pipe and Why Does It Burst?

A frozen pipe is a water pipe where liquid water inside has turned to solid ice. The ice forms when the pipe temperature falls to the freezing point of water or below. Ice takes up more space than liquid water and this expansion increases internal stress on the pipe wall and fittings.

When part of a pipe freezes, liquid water often remains trapped between the ice blockage and a closed valve or fixture. As more water in that section cools and freezes, the trapped volume has no room to expand. Pressure inside the pipe rises far above normal operating levels. Copper, galvanized steel, PVC, and PEX pipes all face this pressure, although each material responds in a different way.

The pipe tends to fail at its weakest point, which may be a thin section, a corroded area, a threaded joint, or a fitting. The result is a crack or complete rupture that opens once the ice starts to thaw and water tries to flow again. Even a small opening along that crack can release hundreds of gallons per day and can saturate insulation, drywall, flooring, and framing. This is why frozen pipes are closely linked to significant water damage and why early prevention and careful thawing protect both the plumbing system and the home.

What temperature causes pipes in a home to freeze?

Most residential pipes begin to freeze when surrounding air stays near 20°F or lower for several hours, although pipes in unheated or drafty spaces can start freezing even when temperatures are only slightly below 32°F.

Freezing risk depends on both how cold it gets and how long the cold lasts. Pipes in exterior walls, attics, and crawl spaces cool faster than pipes in conditioned rooms. Uninsulated lines lose heat more quickly than insulated lines, so they reach freezing temperatures sooner and stay frozen longer.

Key factors that affect when pipes begin to freeze include:

Air temperature around the pipe
Duration of cold exposure over several hours or days
Pipe location such as attic, exterior wall, or crawl space
Level of pipe insulation and air leaks around the area
Pipe material and diameter, since thin metal lines cool faster

Which types of pipes are most likely to freeze?

Pipes are most likely to freeze when they combine heat conducting materials such as copper with exposed or unheated locations such as exterior walls, crawl spaces, and attics. Plastic lines such as PEX tolerate freezing better but are still vulnerable when unprotected.

Metal pipes conduct heat away from water more quickly than many plastics, so they cool and freeze faster in cold air. Older homes with long copper or galvanized runs in exterior walls often face higher risk. Any pipe that sits near outside air or in a space without insulation is more exposed to freezing conditions.

Common vulnerable pipes and locations include:

Copper or galvanized lines in exterior walls without insulation
Supply lines that run through unheated attics or crawl spaces
Exterior hose bibs and outdoor spigots with attached or undrained hoses
Long exposed sections of pipe in garages, basements, or under raised homes

What happens when water pipes freeze in a home?

When water inside a pipe freezes it expands and presses against the pipe wall. This expansion raises internal pressure between the ice blockage and closed fixtures. The extra pressure can crack or burst the pipe once flow returns during thawing.
A frozen pipe forms when liquid water changes to solid ice along a section of the plumbing system. Ice occupies more volume than liquid water. The expanding ice pushes against liquid water trapped between the blockage and a closed tap or valve and pressure increases in that segment.

Pressure continues to rise as more water freezes and has no space to expand. The pipe wall and fittings experience stress far above normal operating conditions. The pipe opens at its weakest point. This point is often a thin wall section, a threaded joint or an aging fitting.

A simple example is a pipe section between a closed shutoff valve and a closed faucet. Ice forms near the coldest spot and blocks that section. Water trapped between the two closures has no way to move so pressure climbs until the pipe splits.

Possible results of a burst frozen pipe include:

Local leaks that damage cabinets and flooring
Water inside walls that saturates insulation and drywall
Widespread flooding that affects multiple rooms and structural framing

What are the most common causes of frozen pipes?

Frozen pipes usually occur when cold air reaches plumbing for many hours and removes heat faster than the pipe can gain it. The main causes combine low temperature unheated spaces, poor insulation and indoor heat set too low or turned off.

Common factors that increase the likelihood of frozen pipes include:

Prolonged outdoor temperatures near 20°F or lower
Pipes installed along exterior walls or in unheated attics crawl spaces or garages
Little or no insulation around pipes or gaps that let cold air blow on them
Long periods when indoor heating is off or the thermostat is set below about 55°F

Vacation homes, empty rentals and storage areas are frequent examples because the heat often stays low and pipes run through unconditioned spaces. Even regions with generally mild winters can experience rare cold fronts that expose uninsulated lines and trigger freezing during a single long night of cold dry wind.

How can you tell if a water pipe is frozen?

Little or no water flow from a faucet and visible frost or bulging on exposed pipes are strong signs that a water pipe is frozen. These changes indicate that ice blocks the line and disrupts normal supply.

Frozen pipes often reveal themselves through changes at fixtures and along visible pipe runs. Some symptoms appear at sinks and showers while others appear on the pipe surface. Each sign signals that water has turned to ice and that pressure inside the line may increase.

Common signs that a water pipe is frozen include:

No water or a weak trickle when a faucet is opened
Toilet tanks that do not refill or refill much more slowly than normal
Frost ice or condensation on exposed pipe sections
Bulging or misshapen areas along a visible pipe
Unusual sounds such as gurgling or banging when taps are opened

If one pipe appears frozen, other pipes in similar locations are often at risk as well, especially lines in the same exterior wall or unheated space. Checking multiple fixtures on different branches helps narrow down which part of the plumbing system is affected and reveals how far the freezing extends.

How do you safely thaw an accessible frozen pipe?

A frozen pipe thaws most safely when the affected faucet is open, gentle heat is applied from the faucet back toward the frozen area, and the pipe is watched closely for returning flow and leaks.

Safe thawing begins with pressure relief. Opening the tap at the end of the frozen run allows any moving water and expanding ice to escape through the fixture rather than through a crack in the pipe wall. This step reduces stress on fittings and lowers the chance of a sudden burst.

Next, warm the surrounding area so the pipe does not sit in very cold air. Apply slow steady heat with a hair dryer or warm towels, starting at the faucet end and moving along the pipe toward the suspected frozen section. This approach melts ice gradually and encourages water to flow out through the open tap as the blockage clears.

Many homeowners use this gentle method for pipes they can see and reach, while pipes hidden behind walls need a different process that relies on warming the space rather than direct contact heat.

What is the step by step process for thawing a frozen pipe?

The basic process is simple. Open the tap, warm the area, apply gentle heat from the faucet end back toward the frozen section, and watch the pipe closely for returning flow and any leaks.

Open the affected faucet. Turn on both hot and cold handles if the tap has two supplies.
Raise the thermostat to warm the home so room air stays at least in the mid fifties.
Open cabinet doors or access panels so warm air can reach the pipe.
Plug in a hair dryer or prepare warm towels and keep cords and plugs away from any standing water.
Apply gentle heat at the faucet end of the pipe. Move the dryer or warm towel slowly along the pipe toward the suspected frozen area.
Continue warming the pipe while keeping the faucet open. Monitor the flow as water begins to run and listen for dripping behind walls or under cabinets.
Inspect the pipe and nearby surfaces for damp spots or active drips. If you see leaks or notice water stains, shut off the main water supply and arrange professional pipe repair or emergency plumbing service.

Always keep electrical devices away from water and combustible materials. Never leave a heater or dryer running unattended while you work on the pipe.

How can you thaw pipes in hard to reach areas without opening walls?

Hidden pipes usually thaw more safely when you warm the surrounding area instead of trying to reach the pipe directly. Gradual heat raises the temperature of wall cavities and ceilings while you monitor fixtures for returning flow.

Useful ways to warm spaces around hidden pipes include:

Raise the thermostat and keep interior doors open so warm air circulates
Use safe space heaters to warm rooms where pipes run and follow all safety instructions
Increase warmth in basements crawl spaces or utility rooms that contain supply lines

This process can take several hours in very cold weather, especially in poorly insulated areas. Check faucets and toilets on the affected branch from time to time to see whether flow improves.

Stop do it yourself efforts and seek professional help if you notice:

Bulging or sagging walls or ceilings that suggest trapped water
Continued lack of water flow after extended warming
Any signs of leaking water, damp spots, or new stains on walls floors or ceilings

These signs indicate that the pipe may already be damaged and requires a trained plumber to reduce further water damage and repair the line safely.

What mistakes should you avoid when thawing frozen pipes?

Open flames, extreme heat, and closed faucets during thawing create a high risk of fire, pipe damage, and sudden bursts. Safe thawing keeps heat gentle, water flowing, and electrical devices away from standing water.
Some actions increase danger instead of reducing it. Intense heat can soften plastic pipes or weaken soldered joints. Closed fixtures trap expanding water and raise pressure instead of relieving it. Unsafe heaters can ignite nearby materials or cause electric shock if they contact water.

Mistakes to avoid when thawing frozen pipes include:

No propane torch or other open flame on any pipe
No very hot devices on plastic pipes or fittings
Do not leave heaters or hair dryers running unattended
Do not keep the faucet closed while you apply heat

If a pipe bursts, act in a calm and direct sequence. Locate and close the main shutoff valve for the building. Open several faucets to drain remaining water from the system. Contact a plumber or an emergency plumbing service to inspect the damage, repair the broken section, and check nearby lines for hidden leaks. This response limits flooding and protects walls, floors and structural framing from further water damage.

How can you prevent pipes from freezing before a cold front?

Prevention keeps pipes above freezing temperature by combining steady indoor heat, insulation on exposed lines, sealed drafts, and a light drip from selected faucets during long periods of cold weather. These steps reduce the chance that water inside pipes can turn to ice.

A good prevention plan treats the home as a single system. Indoor measures protect pipes in conditioned rooms and wall cavities. Outdoor and unheated space measures protect exposed lines, hose bibs, and plumbing in attics, crawl spaces, and garages.

Before a forecast cold front, maintain indoor temperature at or above about fifty five degrees Fahrenheit for several hours. Close and seal obvious air leaks around doors and windows so cold air does not flow across pipes. Prepare to insulate vulnerable lines and set a slow drip on chosen faucets during the coldest part of the night.

The next sections explain practical indoor and outdoor steps in more detail so homeowners can combine them into a simple checklist before each freeze.

What can you do inside the home to reduce the risk of frozen pipes?

Indoor prevention focuses on simple actions. Keep heat on, open cabinets under sinks on exterior walls, allow a slow drip from selected faucets, and keep interior doors open so warm air can reach vulnerable pipes.

These measures help both pressure relief and heat circulation. A consistent thermostat setting keeps room air above freezing, and open paths for air let that warmth reach pipes that sit near cold outer surfaces.

Indoor steps that reduce the risk of frozen pipes include:

Maintain a steady thermostat setting at or above fifty five degrees Fahrenheit during cold weather. This keeps water in pipes above the freezing point.
Open cabinets under sinks that sit on exterior walls. This allows warm room air to circulate around supply lines and reduces cold spots.
Allow a slow drip from specific faucets on long or exposed runs. Moving water relieves pressure and makes freezing less likely inside the pipe.
Keep interior doors open so warm air can travel through halls and rooms. This balances temperatures and reduces extreme cold in seldom used spaces.

Each small change supports the others. Together they keep water moving, prevent trapped pressure, and help room air protect hidden sections of the plumbing system.

How can you protect outdoor and unheated areas from freezing pipes?

Outdoor and unheated areas need direct protection because air around those pipes cools quickly. The goal is to remove standing water from exposed fixtures, cover vulnerable points, and insulate or warm lines that pass through unconditioned spaces.

Key prevention steps for outdoor and unheated spaces include:

Disconnect and drain garden hoses from outdoor spigots and hose bibs. Water trapped in hoses and fittings can freeze and transfer stress into the supply line.
Install insulated covers on outdoor faucets. Foam covers reduce exposure to wind and direct contact with freezing air.
Wrap exposed pipes in crawl spaces, garages, and attics with pipe sleeves or insulated wraps. Added insulation slows heat loss from water inside the line.
Consider heat tape or heat cables rated for plumbing use and listed by recognized testing labs. Apply them according to manufacturer instructions and confirm that outlets and circuits can support the load.

These measures matter most for older homes and properties with long runs of pipe in unheated utility areas. Extra attention in these spaces reduces the chance of frozen sections that can crack and leak when temperatures drop sharply.

When does a frozen pipe need professional plumbing help?

Professional plumbing help is needed when a frozen pipe bursts, when several fixtures lose water at the same time, or when freezing affects hidden or hard to reach lines where leaks are likely and difficult to see.
Minor surface frost on an exposed pipe sometimes clears with careful warming. More serious signs indicate that the plumbing system requires a trained plumber with proper tools. Professional inspection locates damage, assesses pressure related risks, and prevents small cracks from turning into large leaks.

Situations that require professional plumbing help include:

A pipe has burst or is actively leaking water
No water or very low flow appears at several fixtures on the same branch
Water stains, damp patches, or bulging areas appear on walls ceilings or floors
The same section of pipe freezes repeatedly even after basic prevention steps
Uncertainty about the main shutoff valve location or the layout of the pipe run

Plumbers can use leak detection equipment, pressure gauges, and camera inspection to locate hidden damage inside walls, floors, and ceilings. They repair or replace cracked sections and check nearby joints and fittings for stress. This level of assessment protects the structure from further water damage and restores normal flow in a controlled and safe way.

Why contact Central Plumbing for frozen pipe repair in Baton Rouge?

Central Plumbing in Baton Rouge has served local homes and businesses since 1974. The company is family owned and operated, with fourth generation master plumber oversight on service quality. Licensed, bonded, and insured technicians handle water, gas, and sewer lines with established procedures for frozen pipe repair and leak detection. The team provides twenty four hour emergency service and uses a flat rate pricing structure so customers know the service cost before work begins.

Homeowners can call Central Plumbing for frozen pipe inspection, leak detection, pipe repair, and winterization support. Dispatchers connect callers with technicians who understand frozen pipe damage and have access to camera inspection and repair equipment. This combination of experience, clear pricing, and rapid response helps protect walls, floors, and foundations from water damage when pipes freeze or burst during a cold spell.

Conclusion

A frozen pipe checklist helps you recognize risk early, use simple prevention steps before each cold front, respond quickly when pipes freeze, and contact a plumber when damage or hidden leaks create a high level of risk.

Each winter season, treat frozen pipe protection as a repeated routine instead of a one time emergency task. A short checklist guides you through understanding how freezing works, spotting early warning signs, thawing safely, and calling for help when needed.

Use this simple action flow to protect your home:

Understand what happens when pipes freeze and how pressure leads to bursts.
Spot signs of frozen pipes early by watching flow at faucets and toilets.
Thaw accessible frozen pipes gently while keeping faucets open and monitoring for leaks.
Avoid risky methods such as open flames and extreme heat on plastic lines.
Use prevention steps before each cold front with steady indoor heat and insulated exposed pipes.
Call a plumber when bursts occur, several fixtures lose water, or freezing repeats in the same area.
Review and update your checklist every winter so it matches your plumbing layout and past experiences.

Preparedness reduces the chance of sudden water damage and supports a calm, organized response whenever temperatures drop.