What should I do first when a pipe bursts in a freeze?
Close the main shut-off, open a faucet on the lowest floor to relieve pressure, and keep electrical equipment away from the water. Then call. The thaw can release more water than expected, so the first minutes are about stopping the flow.
Once the main is closed, the water in the lines drains out at the open faucet and the flow slows. Leave that faucet open while the house drains, and keep a bucket under it if water is still coming. Do not try to repair the pipe with tape or sealant until it is safe to work on, because the joint may come under pressure again when the line refills.
If the water has reached a light fixture, an outlet or an appliance, turn off the circuit at the panel only if the panel is dry and you can reach it without wading. Otherwise leave the power off and say so when you call.
Does a frozen pipe always burst?
No. A line can freeze solid without splitting, because the pipe may flex, and it can split later on the thaw. The split is what causes the damage, and it often shows only when the water starts to move again.
A frozen pipe is not automatically broken, but it should be checked. Turn the tap on slowly once the house is warm enough. If nothing comes out, or the flow is weak and rusty, call a plumber rather than forcing it, because a hard thaw can split a joint that was holding a little water.
The thaw is the moment to be alert. Listen for running water in the walls, check the ceilings below the pipes and look at the meter if you have one. A drip that starts on a mild afternoon is often the first sign of a split from the previous week.
How far does a leak from a frozen line spread?
Further than the stain. Water follows the framing, runs down inside the wall and along the top of the floor joists, and can reach a room several metres from the break. The drying plan covers the whole path, not just the visible patch.
A leak inside a wall travels down the stud bays until it meets a plate or a joist, then runs along that line until it finds an opening. A ceiling stain in a hallway may have come from a bathroom two rooms away, so crews measure the path with readings in the framing and mark each point the water reached.
The reach is recorded on a plan of the house so the repair trades know where the wet framing is before they open anything. That record also decides which materials come out and which dry in place.
Will the insurer pay for a frozen pipe?
Many standard homeowner policies cover sudden water damage from a burst pipe, but the terms differ, and some exclude damage from freezing when the heat was off or the house was unoccupied. Read the policy, keep the records and ask the insurer in writing what it is covering.
The most useful record for a claim is the shut-off time, the photographs of the damage and the readings that show how far the water went. Keep the failed pipe section if it is replaced, because the break itself is evidence of how the line failed.
Massachusetts consumers are directed first to the insurer or the producer, and then to the Division of Insurance, which takes complaints and tracks them. This page does not decide what the policy covers.
How do I protect the lines before the next freeze?
Insulate the exposed lines, seal the gaps where cold air reaches them, keep the heat at a steady level and know where the main is. A plumber can advise on heat tape for the most exposed runs.
Lines in outside walls, in garages and in the crawl space are the most at risk. Foam insulation on the exposed runs and a sealed opening where the line enters the house are cheap steps that reduce the risk considerably.
On the coldest nights, let the taps served by the most exposed line drip slightly, and keep cabinet doors open under sinks on the outside walls so warm air reaches the pipes.
