Frozen pipe repair cost

Thawing a frozen pipe costs $200 to $700 if it has not split, and $400 to $3,000 if it has. The gap between those two numbers is the whole reason to act on a pipe that has stopped flowing rather than wait and see.

A frozen pipe is not yet an emergency. A frozen pipe that bursts while you are out is.

What it costs

What to do right now

If a tap has stopped flowing in freezing weather, the pipe feeding it is frozen and it is still whole. That is the good outcome, and there is a window to keep it that way.

Leave the tap open. As the ice melts, water needs somewhere to go. A closed tap is what turns a frozen pipe into a split one.

Find the shut-off and check it turns, before you start warming anything. If the pipe has already split, you will find out the moment the ice clears, and you will have seconds.

Warm it gently, from the tap end back toward the frozen section. A hair dryer, a heat gun on low, warm towels, or a space heater in the room. Working from the tap end gives melting water an escape.

Never use an open flame. Blowtorches on frozen pipes start house fires every winter, and on plastic pipe they simply melt it.

Open the cabinet doors under the sink so house heat reaches the pipe.

If you cannot find it, cannot reach it, or the pipe is inside a wall, that is the call. Thawing inside a wall usually means opening the wall.

Why it splits where it does

Ice does not burst the pipe by expanding against it. It expands along the pipe, pushing the water ahead of it toward a closed tap. The pressure builds in that trapped column, and the pipe fails at the weakest point in the stretch between the ice and the tap.

That is why a split is often several feet away from the frozen section, and why leaving a tap open genuinely helps: it removes the closed end.

Where it happens

Almost always in a pipe that has no house heat around it:

• Crawl spaces and unheated basements
• Attic runs, particularly where insulation was pushed aside
• Exterior walls, especially under a kitchen sink on a north wall
• Garages, and pipes to an outside tap
• Unheated additions and enclosed porches

A pipe inside a heated wall, in a house being heated, does not freeze. If yours did, something is missing: insulation displaced, a soffit open to the attic, a vent blowing cold air at it.

What prevents it, in order of value

1. Disconnect and drain hose bibs every autumn. A hose left connected traps water at the tap and splits the pipe behind the wall. This is the single most common winter plumbing failure and it costs nothing to prevent.
2. Insulate the pipes you can reach in crawl spaces, attics and garages. Foam sleeve is about $2 a foot and takes an afternoon.
3. Open cabinet doors on exterior walls when it goes below freezing.
4. Let one tap drip in a hard freeze, at the fixture furthest from the main. A pencil-thin stream, not a drip, on the cold side.
5. Seal the air leaks that let outside air reach the pipe. A pipe fails because cold air is moving past it, not because the room is cool.
6. Leaving for the winter: set the heating to 55°F rather than off, or drain the system properly. Most insurers require maintained heat for a frozen pipe claim.

Heat cable is the last resort rather than the first. It works, it needs power, and it has a service life measured in years rather than decades.

Frequently asked questions

How long until a frozen pipe bursts?

There is no reliable interval. It depends on how much water is trapped, how fast it is freezing, and where the weak point is. Some hold for days; some split within an hour. Treat a stopped tap as time-limited.

Can I just wait for the weather to warm up?

Sometimes it works and you will not know until it does not. The failure happens during the thaw as often as during the freeze, and it happens while nobody is watching.

Will insurance cover the damage?

Usually, if you maintained heat in the house. Policies commonly exclude frozen pipe damage where the property was unoccupied and unheated, which is exactly the scenario that produces the worst ones.

My pipes make banging noises after a freeze.

Water hammer, usually because air got into the system. Turn every tap on and let them run until the flow is smooth. If it persists, an arrestor is $150 to $400.

The tap works but the flow is weak.

Partial blockage: ice still in the line, or debris shaken loose by it. Leave it running gently and it often clears. If it does not, and it is one fixture, check the aerator first.