Pipes Frozen? What to Do (and Not Do) to Thaw Them Safely

You turn on a faucet on a freezing morning and get a trickle or nothing at all. The short answer: you almost certainly have a frozen pipe, and the job now is to thaw it gently and safely — with warm air, not open flame — while keeping the faucet open so the melting ice has somewhere to go. If you find a burst pipe instead, the job changes immediately: shut off the water and call a plumber.

Confirm it is frozen, not something else

First, check whether the problem is one faucet or the whole house. If a single faucet is dead while others work, the frozen section is on that fixture's supply line. If nothing in the house runs, the frozen spot is likely at the main line entry or the meter — and if the meter is the frozen point, call your water utility, since the meter itself is usually their equipment.

Frozen pipes happen most often in exterior walls, unheated basements and crawlspaces, attics, garages, and anywhere a pipe runs along an outside wall with poor insulation. A pipe that froze once will freeze again in the same spot, so note the location for prevention later.

Thaw it the safe way

1. Open the affected faucet. Leave both hot and cold handles open (or the single handle in the middle). As the ice melts, water needs somewhere to go, and the open faucet relieves pressure that could otherwise split the pipe. 2. Find the frozen section. Feel along the pipe: the frozen part will be noticeably colder, and may have frost on the outside. Start thawing from the faucet end and work back toward the blockage, so melting water can escape through the open tap instead of building pressure behind the ice. 3. Apply gentle heat. A hair dryer on a low-to-medium setting, a heating pad wrapped around the pipe, or warm towels soaked in hot water and wrapped around the section all work. Move the heat source along the pipe slowly; don't park a hair dryer on one spot. 4. Be patient. Thawing can take 30 minutes or more depending on the length of the frozen section. Don't rush it.

What never to do

Never use a blowtorch, propane heater, kerosene heater, or any open flame on a frozen pipe — this is how house fires start, and it can also damage solder joints and crack the pipe. Never pour boiling water directly on a frozen pipe either; the thermal shock can crack it. And never use an electric space heater unattended in a crawlspace or near insulation to thaw a pipe — if you use one, stay with it and keep it clear of anything flammable.

If the pipe has burst

If you find water spraying, a split in the pipe, or a rapidly spreading wet spot, stop thawing and shut off the main water supply immediately — the shutoff is usually near where the line enters the house, or at the street meter. Open faucets to drain the system, move valuables and electronics away from the water, and call a plumber right away. A burst pipe can release many gallons per minute, and the water damage bill grows far faster than the plumbing repair bill. If water is near electrical panels, outlets, or appliances, don't wade in — turn off power to the affected area at the breaker first if you can do so safely, or call for help.

A burst-pipe repair itself is usually a section replacement, commonly $200 to $500 for an accessible pipe, more if the burst is inside a wall or under a slab and requires opening and restoring finishes.

Preventing the next freeze

Once the immediate crisis is over, protect the spot that froze: insulate the pipe with foam sleeves (roughly $1 to $3 per six-foot length), seal air leaks near it with caulk or spray foam, and keep cabinet doors open on exterior-wall sinks during hard freezes so warm house air reaches the pipes. On nights forecast below about 20°F, letting a faucet on an exterior wall drip slightly keeps water moving, which is much harder to freeze. And if you leave the house for days in winter, don't turn the heat off — set it no lower than about 55°F. The heating bill is far cheaper than a burst pipe.

On ZIP Pros — "Pros in your ZIP" — describe the problem once and get free quotes from local plumbing pros, with real starting prices shown up front. Mention whether the pipe is frozen or burst and where it is — that determines whether it is a thawing visit or an emergency repair.