Frozen pipe thawing and burst pipe repair
When a pipe freezes, the risk is not just the ice. Pressure builds behind it, and the line can split. Safe thawing and a careful leak check come first.
- Thawing methodsControlled heat, never open flame
- RepairsCopper, PEX, CPVC and galvanized lines
- PreventionInsulation, heat cable, air sealing
Why pipes freeze and why they burst
Water expands as it freezes. When water in a pipe turns to ice, it forms a blockage, and as more water freezes, pressure builds in the section between the ice and a closed faucet. That pressure, not the ice itself, is what usually splits the pipe. The break often appears some distance from the frozen section, and the leak may not show until the ice thaws and water starts flowing again.
Pipes at the greatest risk are those in unheated or poorly insulated spaces: crawlspaces, attics, garages, exterior walls, under kitchen and bathroom sinks on outside walls, and outdoor hose bibs. Air leaks near pipes make the problem worse by letting cold air blow directly onto them.
If you suspect a frozen pipe, acting quickly can prevent a break. If a pipe has already burst, shutting off the water and getting help fast limits the damage.
How to tell a pipe may be frozen
These signs usually appear on the coldest mornings, especially after a sharp overnight drop.
- No water or a trickle at a faucetWhen other fixtures work but one does not, the supply line to that fixture may be frozen somewhere along its route.
- Frost on exposed pipeVisible frost on a pipe in a crawlspace or basement is a strong sign the water inside has frozen.
- Odd smells from drainsA frozen or partially blocked line can prevent odors from venting normally, pushing smells back into the room.
- Bulging or cracked pipeA pipe that looks swollen or cracked may have already split and will leak once thawing begins.
- Water stains appearing on walls or ceilingsA burst pipe hidden in a wall or ceiling can show up as a spreading stain or sagging drywall.
- Hissing or running water soundsSounds of flowing water when all fixtures are off can mean a thawed pipe is now leaking inside a wall.
How we handle frozen and burst pipes
Stop the water if needed
If a pipe has burst, we help you locate and close the main shutoff by phone and confirm the leak has stopped.
Locate the frozen section
The technician traces the affected line to find where it runs through cold areas and where the ice is likely to be.
Thaw safely
Controlled heat is applied gradually with the faucet open so meltwater and pressure can escape. Open flames are never used.
Repair any breaks
Split or damaged sections are cut out and replaced with materials matched to your existing piping.
Check and protect
The line is pressurized and checked for leaks, and we recommend insulation, heat cable or air sealing to prevent a repeat.
Safe thawing and the prevention steps that work
Thawing must be done carefully. Heat is applied gradually, working from the faucet end back toward the frozen section so melted water has a path out. Keeping the faucet open relieves pressure and shows when flow returns. Open flames from torches or heaters create a serious fire risk inside walls and floors, and overheating a pipe can damage it or its joints. Homeowners can safely use a hair dryer or warm towels on exposed pipe, but pipes hidden in walls or ceilings are best left to a professional.
Prevention focuses on keeping pipes above freezing. Insulating pipes in unheated spaces slows heat loss, and sealing air leaks near pipes stops cold drafts from reaching them. For lines that remain vulnerable, listed heat cable installed according to the manufacturer's instructions provides active protection. During severe cold, opening cabinet doors on exterior walls, letting a faucet drip on vulnerable lines and keeping the thermostat at a steady temperature, including at night and when traveling, all reduce the risk. Outdoor hose bibs should be disconnected from hoses and shut off or replaced with frost-proof models.
If a pipe bursts right now
Close the main water shutoff, turn off the water heater if the leak is large, move valuables away from the water and, if water is near electrical outlets or fixtures, stay clear and shut off power to that area at the breaker if it is safe to reach. Then call for help.
Why pipes freeze and how to protect them
Pipes freeze where they are exposed to cold air, typically in exterior walls, crawlspaces, attics, garages and unheated basements. Wind can drive cold air through small gaps, freezing pipes even when the rest of the home is warm.
When water freezes, it expands and increases pressure between the ice blockage and the closed faucet. That pressure, not the ice itself, often causes pipes to split. Leaks may not appear until the pipe thaws.
Thawing should be done carefully using safe heat sources, starting from the faucet end and working toward the frozen section. Open flames and high-heat devices can damage pipes and create fire hazards. Once thawed, pipes should be inspected for splits or leaks.
Preventing future freezes may involve insulating pipes, sealing drafts, rerouting vulnerable lines or installing heat cable where appropriate. Keeping cabinet doors open on exterior walls and allowing faucets to drip during extreme cold can also help.
Frozen pipe mistakes
These actions can cause damage or safety hazards.
Using open flames
Torches can ignite building materials and damage pipes.
Ignoring small leaks after thawing
Small splits can worsen quickly once water pressure returns.
Turning off heat in vacant homes
Unheated homes are at high risk of frozen pipes. Maintain safe temperatures or winterize the plumbing.
Forgetting outdoor hoses
Hoses left connected can trap water and cause frost-proof faucets to freeze and split.
Not knowing the main shutoff location
Quick access to the main shutoff can limit damage when a pipe bursts.
What determines the cost of frozen pipe work
- Location of the freeze
- Exposed pipes in basements are quick to thaw and repair. Pipes inside finished walls or ceilings require opening those surfaces.
- Whether the pipe burst
- Thawing alone costs less than thawing plus cutting out and replacing split sections.
- Pipe material
- Copper, PEX, CPVC and older galvanized steel each require different repair methods and materials.
- Prevention upgrades
- Insulation, heat cable and frost-proof hose bibs are quoted as separate options after the immediate repair.
Frozen pipe questions
If the pipe is exposed and you can reach it safely, gentle heat from a hair dryer with the faucet open is reasonable. Never use an open flame, and call a professional if the pipe is hidden, you cannot find the frozen section or you see any leak.
Pressure builds between the ice blockage and a closed faucet. The weakest point in that section gives way, which may be some distance from the ice itself.
A slow drip keeps water moving and relieves pressure in the line, which can help prevent freezing and reduce the chance of a burst.
Keeping the thermostat at a consistent, moderate temperature day and night helps. Pipes in exterior walls and unheated spaces remain at risk even when the living space is warm, so insulation and air sealing matter.
A frozen supply can starve a water heater of cold water, and frozen boiler piping can stop heat delivery. Both should be checked after a freeze.
Frozen line or burst pipe? Call right away
Our dispatcher will help you shut off the water and send a technician to thaw and repair the line.