How to Thaw Frozen Pipes Without Bursting Them

A frozen pipe shows itself when a faucet gives nothing or only a trickle. Thaw it by opening that faucet and warming the pipe from the faucet end toward the frozen section with a hair dryer, heating pad, space heater or hot towels until full pressure returns. Never use an open flame. These steps follow Baltimore City DPW and university extension guidance, with the warning signs that mean it already split.

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Pipe already split or leaking? Close the main valve and call.

Thaw it in this order

Find the main shut-off valve first.
Open the faucet on the frozen line.
Warm the pipe starting at the faucet end.
Keep heating until full pressure returns.
Check every other faucet in the house.

Step 1 of 7

Confirm the pipe is frozen

A faucet that gives nothing or only a trickle in freezing weather has a frozen pipe behind it. Iowa State University Extension notes that pipes in unheated basements, attics and garages freeze most often.

Baltimore City DPW warns that pipes and utility meters freeze when the temperature stays below 25°F for extended periods. When no faucet in the house runs, the freeze is likely at the service line or meter, and the Institute for Business & Home Safety (IBHS) advises calling a plumber instead of thawing it yourself.

Step 2 of 7

Locate the main shut-off valve before you add heat

Texas A&M AgriLife Extension points out that a frozen pipe may already be broken and will start leaking the moment the ice melts. Know where the main valve is, and check that it turns, before you warm anything. Where the main shut-off valve sits in Baltimore homes walks through gate and ball valves.

Step 3 of 7

Open the faucet the frozen pipe feeds

Leave the faucet open the whole time. As the frozen section melts, water starts moving through it, and that flowing water melts the remaining ice faster, according to Iowa State University Extension.

Step 4 of 7

Warm the pipe from the faucet end toward the ice

Start close to the open faucet and work slowly toward the coldest section of pipe, as IBHS and NC State Extension direct. Baltimore City DPW specifically recommends warming a frozen interior pipe with a hair dryer where it enters the house.

An electric hair dryer
An electric heating pad wrapped around the pipe
A portable space heater kept away from anything flammable
Towels soaked in hot water and wrapped around the pipe

Keep cords out of any water, and never run an electrical appliance while standing in water.

Step 5 of 7

Never use an open flame

No blowtorches, kerosene or propane heaters, charcoal stoves or other open flames. Texas A&M AgriLife Extension calls them a serious fire hazard that also releases lethal carbon monoxide, and IBHS warns a flame damages the pipe itself and can start a building fire.

Step 6 of 7

Keep heating until full water pressure returns

A trickle is not a finished thaw. Keep applying heat until the faucet runs at full pressure, then open every other faucet in the home: Texas A&M notes that when one pipe freezes, others often have too.

Step 7 of 7

Call a licensed plumber when you can’t reach or thaw it

Iowa State University Extension advises calling a licensed plumber when the frozen area can’t be found, sits inside a wall or ceiling, or won’t thaw. Speedy Plumbing Baltimore thaws frozen lines and repairs any section that split, any hour, at (410) 555-0199.

Why a frozen pipe bursts where there is no ice

A frozen pipe bursts from pressure, not from the ice itself. IBHS explains that ice blocking the pipe keeps expanding, which raises water pressure between the blockage and the closed faucet; the pipe usually splits where little or no ice has formed.

That is why an open faucet matters: it relieves the pressure. When a split has already happened, water appears at the break as the line thaws; close the main valve at the first sign of it and follow the burst pipe first steps.

How often Baltimore gets cold enough to freeze pipes

NOAA’s 1991–2020 climate normals for BWI Marshall Airport show how often Baltimore crosses the temperatures that freeze household pipes.

January normal low: 25.4°F
Nights at or below 32°F, per year: 93.2
Nights at or below 20°F, per year: 20.8
DPW freeze warning point: Below 25°F

University of Illinois Building Research Council tests, published by IBHS, found uninsulated attic pipes began freezing when it fell to 20°F outside, and pipes in drafts freeze at warmer temperatures. Keeping them from freezing in the first place is covered in how to prevent frozen pipes in a Baltimore winter.

Frozen pipe questions

Can I thaw a frozen pipe with a hair dryer?

Yes. Baltimore City DPW recommends warming a frozen interior pipe with hot air from a hair dryer where it enters the house. Open the faucet first, start near the faucet end and keep cords away from water.

How do I know if a frozen pipe has already burst?

The leak shows up as the ice melts: water appears at a split or a joint once flow returns. Know where the main valve is before thawing, and close it at the first drip or spray.

Should I leave a faucet dripping after the pipe thaws?

Yes, while temperatures stay below freezing. Baltimore City DPW recommends a thin, steady stream of cold water about as thick as a pencil lead from a faucet on the lowest level of the home.

When the thawed pipe leaks

A split found after thawing needs the damaged length cut out and replaced, then a pressure test before the water stays on. See how that repair works on the frozen and burst pipe repair in Baltimore page.

Sources

Checked 2026-09-13. Plumbing and safety guidance changes; follow your utility’s and insurer’s current instructions.

No water or a split pipe?

Speedy Plumbing Baltimore thaws frozen lines and repairs the split. The line is answered 24 hours a day.

Call (410) 555-0199