Frozen Pipe Thawing and Repair
A frozen pipe has not necessarily burst yet, which makes this the rare plumbing emergency you can still get ahead of. Open the affected faucet, apply gentle heat from the faucet end backward, and never use an open flame. Professional thawing typically runs $250 to $700, far less than the repair if it splits.
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How urgent is this? Urgent but not always after-hours. A frozen pipe that has not split is a problem you can often manage yourself. The moment water appears, it becomes a burst pipe emergency.
Typical cost: $250 to $700 nationally. Thawing alone sits at the low end. If the pipe split while frozen, add burst pipe repair costs. Frozen buried service lines are a separate and far more expensive category, and are often the water utility's responsibility rather than yours.
Warning signs
- No water or a thin trickle from one fixture while others run normally
- Visible frost or bulging on an exposed section of pipe
- A pipe that is noticeably colder to the touch than the rest of the run
- Sudden loss of flow during a cold snap, especially at an exterior wall fixture
- Unusual gurgling or banging when a fixture is opened
What causes it
- Pipe routed through an unheated attic, crawlspace, garage, or exterior wall cavity
- Interrupted heating from a furnace failure or power outage during freezing weather
- Wind driving cold air into an uninsulated wall cavity or rim joist
- An outdoor hose left connected to a hose bibb over winter
- A vacant property with the thermostat set too low or off entirely
What to do before the plumber arrives
- Open the faucet served by the frozen pipe so melting ice has an escape path
- Apply gentle heat with a hair dryer or space heater, working from the faucet end toward the frozen section
- Never use a torch, propane heater, or any open flame on a pipe
- Open cabinet doors under sinks on exterior walls to let room heat reach the pipes
- Locate your main shutoff now, before the ice clears and a hidden split starts releasing water
What the plumber will actually do
Locate the frozen section
The plumber traces the run from the affected fixture backward to find the blockage, usually where the pipe passes through unconditioned space.
Open the fixture and thaw from the outlet inward
The downstream faucet is opened so melting water and pressure have somewhere to go, then controlled heat is applied starting nearest the faucet and working toward the blockage.
Apply controlled heat
Heat guns, heat trace, or pipe thawing equipment is used. Open flame is never appropriate and is a leading cause of house fires during cold snaps.
Inspect for splits under pressure
Once flow returns the run is watched under full pressure, because a split hidden by ice only reveals itself when the ice clears.
Address the exposure
Insulation, heat trace, or rerouting is recommended for the section that froze, since the same run will freeze again in the next comparable cold event.
Frozen pipes FAQ
How do I know whether a frozen pipe has already burst?
You usually cannot tell while it is still frozen, because the ice plugs the split. That is exactly why you should locate and be ready at the main shutoff before thawing begins. If water appears as flow returns, close the main immediately.
Should I leave faucets dripping during a cold snap?
Yes, for fixtures served by pipes running through unheated or exterior-wall space. A pencil-thin stream from the furthest fixture keeps water moving and relieves the pressure buildup that actually splits pipes. The wasted water costs far less than one repair.
How long does a pipe take to freeze?
Exposed pipe in a wall cavity can freeze in six to eight hours at 20°F, and considerably faster with wind driving into the cavity. Well-insulated pipe in conditioned space can survive days of the same weather. The exposure matters far more than the temperature.
My whole house lost water in a freeze. What now?
A total loss of water usually means the freeze is upstream of the house, at the meter or in the buried service line, rather than in an interior branch. That is normally the utility's side. Call your water utility first, since a plumber cannot thaw a buried main.
Related services
- Emergency Burst Pipe RepairA burst pipe releases water continuously until the supply is shut off. Emergency repair covers isolation, pipe section replacement, and pressure testing.
- Main Water Line RepairRepair and replacement of the buried water service line between the meter and the house, including trenchless replacement options.
- Emergency Leak DetectionNon-invasive location of hidden water leaks behind walls, under floors, and beneath slabs using acoustic, thermal, and pressure testing equipment.
- Sewer Line Repair and ReplacementRepair, lining, or replacement of damaged sewer laterals, including trenchless options that avoid excavating the yard.
Emergency guides
- Frozen Pipes: What to Do Before They BurstA frozen pipe has not necessarily failed yet. Thawing it correctly, and being ready at the shutoff, is what keeps it from becoming a burst pipe.
- Winterizing Your PlumbingThe autumn work that prevents the winter emergency, and the full winterization procedure for properties left vacant in freezing weather.
- How to Shut Off Your Water in an EmergencyFind and operate your main water shutoff before you need it. The single most valuable thing a homeowner can know during a plumbing emergency.
Cost guides
- Burst Pipe Repair CostWhat burst pipe repair costs by location and pipe type, plus the water damage costs that usually exceed the plumbing.
- Drain Cleaning CostWhat drain and sewer clearing costs by method and location, and when jetting is worth the premium over cabling.
- Sewer Line Repair and Replacement CostWhat sewer lateral repair costs by method, including trenchless lining and pipe bursting, and how to compare quotes honestly.
Common questions
- Costs and Billing QuestionsHow emergency plumbing is priced, what the premiums are, and which questions to ask before dispatch.
- Water Heater QuestionsLeaks, no hot water, strange noises, safety valves, and the repair-or-replace decision.
- Drain and Sewer QuestionsBlocked drains, main line backups, recurring clogs, and what not to put down them.
Related articles
- Why Pipes Burst in Cold States and Catastrophically in Warm OnesMinnesota freezes harder than Texas every year and loses fewer pipes. The reason is preparation, not temperature.
- The Leaks You Never See Until the Bill ArrivesHidden leaks waste thousands of gallons without a single visible drop. How to find them in half an hour, for free.
- What Emergency Plumbing Actually Costs, and WhyA plain breakdown of after-hours rates, call-out fees, and the four questions that change your invoice.