How to Fix Frozen Pipes: Thawing, Prevention, and Burst Pipe Emergency Response (2026)
Frozen pipes stop water flow and can burst, causing thousands in water damage. This guide covers locating the frozen section, safely thawing it, and preventing pipes from freezing again — and what to do if a pipe has already burst.
Frozen pipe thawing: (1) Open the faucet the pipe feeds — this relieves pressure as the ice melts and tells you when flow is restored. (2) Locate the frozen section — unheated crawl spaces, exterior walls, and near garage walls are most common. (3) Thaw with a hair dryer on the pipe surface, working from the faucet end toward the frozen section. Never use an open flame. (4) If you cannot reach the frozen section (inside a wall): turn on the heat, open cabinet doors, and wait. Electric pipe heating tape can be applied to accessible sections before the next freeze. (5) If the pipe has burst: shut off the main water valve immediately.
Frequently Asked Questions
How do I find the frozen section of pipe?
Locating the frozen section: (1) Start from the faucet with no flow and trace the pipe back toward the supply. The frozen section is between a working pipe and the dead-flow faucet. (2) Check the usual suspects: pipes in unheated crawl spaces (most common), pipes running through exterior walls (especially north-facing walls), pipes near an uninsulated band joist, pipes near a garage that was left open. (3) Touch the pipe — the frozen section will feel much colder than the surrounding pipe, and you may hear hollow tapping on a frozen section vs. a water-filled pipe. (4) If you turn on the faucet and get a small trickle (not total blockage): the freeze is partial and thawing with heat in the room may restore full flow. (5) In a crawl space, use a flashlight to look for frost on the pipe exterior — frost pinpoints the frozen zone precisely.
What is the safest way to thaw a frozen pipe?
Safe thawing methods (in order of preference): (1) Electric hair dryer — apply on low heat, work back and forth along the pipe starting nearest the open faucet. Most effective for accessible pipes. (2) Electric heating tape — wrap around the pipe and plug in. This is also the best prevention tool. (3) Hot wet towels — wrap hot water-soaked towels around the frozen section, refreshing as they cool. Slow but zero equipment required. (4) Portable electric space heater — point at the frozen pipe section in a closed crawl space or cabinet. Keep water and electricity separated. (5) Never use: open flame (torch, lighter), propane heater in an enclosed space, or a heat gun at high settings. The pipe carries water but is bonded with solder and glue — flame can damage fittings, char nearby framing, or start a fire in the wall cavity. A torch on copper can also turn the pipe brittle.
What do I do if a frozen pipe has burst?
Burst pipe emergency response: (1) Turn off the main water supply valve immediately — it is usually near the water meter, in the utility room, or at the point of entry into the foundation. Know its location before you need it in an emergency. (2) Turn off the water heater (electric: flip breaker; gas: turn to pilot) — running a water heater with no water in it can damage the tank. (3) Open all faucets to drain remaining water from the system. (4) Take photos of the damage for the insurance claim before cleanup. (5) Start drying immediately — mold begins growing in 24–48 hours. Remove standing water, run fans and dehumidifiers. (6) Call a plumber for the pipe repair — a burst pipe requires cutting out the damaged section and installing a coupling or new section. Copper: solder or push-fit coupling. PEX: push-fit or crimp coupling. (7) Before restoring heat and water, inspect the burst section for a second freeze overnight — restore water only when temperatures will remain above freezing.
How do I prevent pipes from freezing again?
Pipe freeze prevention: (1) Pipe insulation foam — wrap any pipe in an unheated space with pipe insulation sleeves (sold in 6-foot sections). Foam pipe insulation costs $0.50–$1 per foot and installs by slitting and pressing over the pipe. (2) Electric pipe heating cable — a thermostat-controlled heat cable wraps around the pipe and automatically turns on when temperatures drop below 38°F. Required for pipes in unheated areas that cannot be insulated enough. (3) Let the faucet drip — if temperatures below 20°F are forecast and you have pipes in exterior walls, let a cold-water faucet on the vulnerable pipe drip at night. Moving water does not freeze as readily. (4) Open cabinet doors under sinks on exterior walls — this allows heated room air to reach the pipes. (5) Insulate the crawl space hatch — an open or missing crawl space access door is one of the top causes of frozen pipes. (6) Keep the garage door closed — pipes in garage walls freeze quickly when the garage is left open in subfreezing weather.
Can I use pipe heating tape on PVC or PEX pipes?
Pipe heating tape compatibility: (1) Self-regulating pipe heating cable (the type sold at home centers) is safe for copper, steel, PVC, and PEX pipes — the cable regulates its own temperature to below the damage threshold of each material. (2) Constant-wattage heat tape (the older coil type) can melt PVC and CPVC if improperly applied — check the label before use. Avoid constant-wattage tape on plastic pipe. (3) Never overlap self-regulating cable on itself — it can overheat at the overlap point. (4) Follow the cable manufacturer's instructions for the specific pipe material. (5) The insulation rule: pipe heating cable works best when covered with pipe insulation foam over the cable — the foam keeps the heat on the pipe rather than heating the crawl space. Without insulation, the cable must work much harder and your energy bill shows it.
Frozen pipe thawing: (1) Open the faucet the pipe feeds — this relieves pressure as the ice melts and tells you when flow is restored. (2) Locate the frozen section — unheated crawl spaces, exterior walls, and near garage walls are most common.
Open the faucet before thawing — the pressure release speeds melting and tells you exactly when flow is restored.
What you need
- Hair dryer or electric pipe heating cable
- Pipe insulation foam (for prevention)
- Flashlight
- Towels (for wet-towel method)
- Main water shutoff location (know this before you need it)
Step 1: Locate the freeze and open the faucet
Open the affected faucet fully. Trace the supply line from the faucet back toward the supply main. Check unheated areas: crawl spaces, exterior walls, garage walls.
Step 2: Apply heat to the frozen section
Apply a hair dryer on low heat to the frozen pipe, working from the open faucet side back toward the frozen section. Move the dryer continuously. Never use open flame.
Step 3: Monitor for flow restoration
Watch the open faucet. When the ice melts, water will begin flowing. After flow is restored, run the faucet at full flow for 2 minutes to flush the system.
Step 4: Prevent the next freeze
Wrap the vulnerable pipe section with foam pipe insulation. For pipes in unheated spaces with recurring freeze risk: install self-regulating electric pipe heating cable under the insulation.
Step 5: If a pipe burst — shut off water immediately
Turn the main water valve off. Open all faucets to drain the system. Call a plumber and document damage for insurance before drying out begins.
Related guides
- How to Fix a Leaking Pipe — pipe joint and pinhole leak repair
- How to Insulate Pipes — foam pipe insulation installation
- How to Fix a Basement Leak — water intrusion from exterior and wall seepage
- Locate the freeze and open the faucet
Open the affected faucet fully to relieve pressure as the ice melts. Trace the supply line from the faucet back toward the supply main. Check unheated crawl spaces, exterior walls, and garage walls — touch the pipe to find the cold section.
- Apply heat to the frozen section
Apply a hair dryer on low heat to the frozen pipe. Work from the faucet side back toward the frozen section — this direction allows meltwater to exit. Move the dryer continuously. Never use open flame or a torch on pipes.
- Monitor for flow restoration
Watch the open faucet. When flow begins, run the faucet at full flow for 2 minutes to flush the system. If flow does not restore within 30 minutes: the freeze may be deeper inside a wall — turn on the heat, open cabinet doors, and wait.
- Prevent the next freeze
Wrap vulnerable pipe sections with foam pipe insulation. For pipes in unheated areas with recurring freeze risk: install self-regulating electric pipe heating cable under the insulation. It turns on automatically when temperatures drop below 38°F.
- Emergency: if a pipe has burst
Turn off the main water valve immediately. Turn off the water heater (electric: flip breaker; gas: turn to pilot). Open all faucets to drain the system. Document damage for insurance before drying begins. Call a plumber for pipe repair.
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