Frozen Pipes: How to Thaw Them and Prevent a Burst

A frozen pipe is a burst on a timer. As water freezes it expands, and the pressure it builds can split the pipe — the flood comes when it thaws. If you catch a pipe while it's still frozen and intact, you have a chance to thaw it safely and avoid the whole mess. Move quickly, but use the right method.

The tell-tale sign: one faucet trickles or gives nothing while others run fine, usually after a hard freeze.

Do these things right now

1. Open the faucet. Open the faucet the frozen pipe feeds — both hot and cold handles. This relieves pressure and gives melting ice somewhere to go. Running water, even a trickle, helps thaw it.

2. Find the frozen section. Follow the pipe from the dead faucet back toward exterior walls, crawlspaces, attics, or unheated areas. Look for frost on the pipe or a bulge. That's where to apply heat.

3. Know where your main shutoff is. If the pipe has already burst (you'll see it once it thaws), you need to shut the main fast. Locate it now, before you start thawing.

4. Apply gentle heat — from the faucet end inward. Start heating near the faucet and work back toward the cold spot, so melting water can escape. Safe heat sources:

• A hair dryer
• A heating pad or heat tape wrapped around the pipe
• Warm, wet towels
• A space heater kept a safe distance away, in a dry spot

Keep the faucet open the whole time. Thawing is slow — give it time.

5. Never use an open flame. No blowtorch, no propane torch, no open flame of any kind. It's a leading cause of house fires and can burst the pipe. Also avoid unattended space heaters and anything electric near standing water.

6. If you can't reach it or it's already burst, call a pro. Pipes inside finished walls or a slab need a plumber. If it bursts, shut off the main and call — see burst pipe steps.

How to know if the pipe already burst

The cruel part of frozen pipes is that the damage often shows up during the thaw, not the freeze. As you warm the pipe, watch for:

• Water appearing where it shouldn't — a wet wall, ceiling stain, or puddle.
• A sudden drop in the trickle at the faucet, or air spitting from the tap.
• A hissing or rushing sound inside the wall.

If any of that happens, shut off your main immediately, open faucets to drain the system, and call a plumber. Catching a split during the thaw — before you've refilled the whole system at pressure — limits the flood. See burst pipe steps.

When to DIY vs. call a pro

Thawing an accessible pipe with a hair dryer or heat tape is a reasonable DIY job. Prevention is all DIY too.

Call a plumber when:

• The frozen pipe is inside a wall, ceiling, or slab you can't reach.
• The pipe has already burst or is leaking.
• Multiple pipes are frozen.
• You can't get water flowing after a solid thawing effort.
• Pipes freeze repeatedly — you may need insulation or rerouting.

Do not use a torch, and don't leave a space heater running unattended near pipes. If a pipe bursts near electrical, cut power to that circuit safely and stay clear.

What not to do

A few common instincts make things worse:

• Don't crank the whole-house heat to 90 and walk away. It won't reach a pipe sealed in an exterior wall fast enough, and it wastes energy. Direct heat at the frozen section instead.
• Don't use a torch, propane heater, or any open flame. Fire risk, and the sudden heat can rupture the pipe.
• Don't leave a space heater unattended or near anything flammable or wet.
• Don't ignore a pipe that thawed on its own. If it froze once, it'll freeze again — insulate it before the next cold snap.
• Don't close the faucet while thawing. The open tap relieves pressure and gives melting water an escape; a closed system is where bursts happen.

What it costs

| Job | Typical 2026 range | |---|---| | DIY thawing (hair dryer, heat tape) | $0–$50 | | Plumber to thaw an inaccessible pipe | $150–$500 | | Burst pipe repair | $150–$1,800 | | Water damage restoration if it bursts | $1,384–$6,384 |

The math is stark: a $30 hair dryer versus a multi-thousand-dollar water-damage claim. For the flooding scenario, see the water damage restoration cost guide; for the pipe fix, plumbing costs. You can also estimate your local cost.

Which pipes freeze first

Not all pipes are equally at risk. Focus your prevention where freezes actually happen:

• Pipes against exterior walls, especially under kitchen and bathroom sinks.
• Runs in unheated spaces — attics, basements, crawlspaces, and garages.
• Outdoor spigots and hose bibs, and the pipe feeding them.
• Pipes near drafts — rim joists, sill plates, and gaps where cold air leaks in.
• Vacation homes and rooms you keep cool — anywhere the heat is low or off.

If freezes keep hitting the same spot, that pipe needs insulation, heat tape, or in stubborn cases, rerouting by a plumber. Chasing the symptom every winter costs more than fixing it once.

Prevent the next freeze

• Keep the house at least 55°F, even when you're away in winter.
• Insulate pipes in attics, crawlspaces, garages, and exterior walls; add heat tape to the most vulnerable runs.
• Let faucets drip on the coldest nights — moving water resists freezing.
• Open cabinet doors under sinks on exterior walls to let warm air reach the pipes.
• Disconnect garden hoses and shut off/drain outdoor spigots before winter.
• Seal drafts near pipes — cold air leaks are where freezes start.

Our winter home prep checklist covers full winterization, and when to call an emergency plumber covers the after-hours call.

FAQ

How do I know a pipe is frozen? One faucet trickles or gives nothing while others run normally, usually after a hard freeze. You may see frost or a bulge on the pipe.

Can I use a torch to thaw a pipe? Never. Open flame is a top cause of house fires and can burst the pipe. Use a hair dryer, heat tape, or warm towels instead.

At what temperature do pipes freeze? Risk rises sharply below about 20°F, especially for uninsulated pipes in unheated spaces. Keeping the home above 55°F and letting faucets drip helps prevent it.

What if the pipe already burst? Shut off your main immediately, drain the lines, document for insurance, and call a plumber. See burst pipe steps.

Should I leave faucets dripping all winter? Only during freezing weather. A slow drip on the coldest nights is cheap insurance against a burst.

How long does it take to thaw a frozen pipe? Anywhere from 30 minutes to several hours, depending on how solidly it's frozen and how accessible it is. Keep the faucet open and apply steady, gentle heat — rushing it with high heat or flame risks a burst.

What should I set my thermostat to when I'm away in winter? At least 55°F, never off. Turning the heat off to save money is how vacation homes and empty rentals end up flooded. If you'll be gone a long stretch in a cold climate, consider shutting off and draining the water supply entirely.

Does insurance cover frozen pipe damage? Usually, if you took reasonable steps to keep the home heated. Insurers may deny claims where the heat was left off. Keep the home warm, document any damage, and file promptly.

Cost figures are 2026 national averages for general information only, not quotes. Your price depends on your specific job, home, and location. Always get a written estimate before authorizing work. Never thaw a pipe with an open flame — it's a fire and burst hazard. If a pipe bursts near electrical wiring, cut power to the circuit safely and call a professional.