Frozen Pipes? How to Thaw Them Safely
Short answerTo thaw a frozen pipe, open the faucet it feeds and heat the pipe gently, starting at the faucet and working back, with a hair dryer, heat lamp or hot wet towels. Never use an open flame or boiling water. Know where your main shutoff is, because the pipe may leak once it thaws.
Safety first
- Know where your main water shutoff is and how to close it before you start. Thawing can reveal a split in the pipe.
- Never thaw a pipe with a torch or other open flame. It is a fire hazard. Boiling water can burn you.
- Be careful with electric heaters and hair dryers near water. Keep them away from puddles to avoid shock. Keep anything that can burn at least 3 feet from a space heater, and turn it off when you leave the room.
Likely causes
| Cause | How to tell | What fixes it |
|---|---|---|
| Pipe along an outside wall, attic or crawl space | One faucet has little or no water after a cold night. | Thaw it, then insulate that section and seal cold air leaks. |
| Heat set too low or turned off | Several faucets stop while the house is cold or empty. | Keep the heat no lower than 55°F. |
| Outdoor faucet or hose line left on | An outdoor faucet stops or the line nearby is frozen. | Disconnect hoses, then shut off and drain the line feeding the outdoor faucet. |
What you need
- Hair dryer, heat lamp or space heater
- Towels soaked in hot water
- Bucket
- Foam pipe insulation
- Flashlight
How to fix it
- Find the frozen section. Check which faucets work. Trace the line to a cold spot on an outside wall, under a sink, or in a crawl space or attic. Look for frost, or a bulge or split in the pipe. If you see a split, close the main valve and call a plumber.
- Open the faucet. Open the faucet on the frozen line so melting water and steam have a way out. Keep buckets nearby. If a leak is possible, shut off the main line first and open other faucets to drain the system.
- Heat gently from the faucet back. Start at the faucet and work toward the frozen section, using a hair dryer, heat lamp, space heater or hot wet towels. Gradual heat keeps trapped water from boiling and protects faucet parts.
- Turn off the water heater if needed. If a hot water or main line is frozen, you may need to turn off the water heater until water is flowing again.
- Check for leaks. When water flows, close the faucets and look along the pipe for drips. Check again after a few hours.
- Protect it from freezing again. Insulate the pipe with foam sleeves that fit snugly and cover all exposed sections. Open cabinet doors under sinks on outside walls. On very cold nights, let hot and cold water trickle from a faucet on an outside wall, and keep the heat at 55°F or more.
When to call a professional
- You cannot find or reach the frozen section, such as inside a wall.
- The pipe is split, bulging or leaking. Shut off the water and call a plumber and your insurance agent.
- Pipes freeze again after you insulate them.
What it costs to have fixed
Pipe Repair is estimated at $130 to $800 nationally. See your state
Common questions
What should I do about frozen pipes?
Find the frozen section, open the faucet and warm the pipe gently from the faucet back. Have the main water shutoff ready in case the pipe has split.
Should I let faucets drip to prevent frozen pipes?
A trickle helps on very cold nights, but it uses water. Utah State Extension calls running water a last resort and notes hot lines can freeze too, so insulate and keep the heat on first.
How low can I set the heat when I go away?
University of Illinois Extension says no lower than 55°F. If you are leaving for a while, have someone check the house daily, or drain and shut off the water system.
Is the frozen pipe on my AC unit the same thing?
No. Ice on an air conditioner line means the cooling system has a problem, not your plumbing. See our guide on an AC that is freezing up.
What temperature do pipes freeze and burst?
Texas guidance is one example: Texas A&M says water pipes have the potential to freeze and burst when the outside temperature reaches 20°F or below. Outdoor faucets and pipes in attics, crawl spaces, garages and poorly insulated outside walls are the most at risk. Source
How do I know if my pipes are frozen?
No water from a faucet or shower is the main sign. The City of Independence, Missouri, for example, says that if only one faucet is dry, or only its hot or cold side, the pipe is usually frozen under that sink. Water in one part of the house but not another points to a freeze inside the home. Source
Can a hot water pipe freeze?
Yes. As an example from Texas, Texas A&M guidance says a hot water line can freeze just as a cold line can if water is not running through it and the water in the pipe has gone cold. Source
Related repairs
- Burst Pipe in House? What to Do First
- Clogged Drain? How to Unclog a Sink or Tub
- Garbage Disposal Not Working? Reset and Unjam It
- Leaky Faucet? How to Fix a Dripping Faucet
- Low Water Pressure in House? How to Find the Cause
- No Hot Water in House? What to Check First
- Sewer Smell in House? Causes and What to Do
- Toilet Keeps Running? How to Stop It Yourself
Last verified 2026-11-01
Sources
- Utah State University Extension: Advice to Prevent Frozen Pipes — Thawing order, safe heat sources, shutting off the main line first, opening faucets, not using boiling water or open flame, insulation guidance, and running water as a last resort
- University of Illinois Extension: Water Pipes — Keeping heat no lower than 55°F, opening cabinet doors, trickling water, draining outdoor lines, no flame, shock warning, and what to do if a pipe bursts
- Ready.gov: Safety Skills — Locating the main water shutoff
- U.S. Fire Administration: Heating Fire Safety — Keeping anything that can burn at least 3 feet from heat sources, and turning space heaters off when leaving the room
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.