TL;DR
Pipes usually fail during the thaw, not during the freeze, so the hours after temperatures rise back above 32 degrees F are when to inspect. Find and dry any water within the first day, because common remediation guidance treats roughly 24 to 48 hours as the window before growth begins on wet materials. Anything soaked into building materials is a restoration job, not a cleaning one.
The thaw is the dangerous part
This surprises people, and it changes when you should be paying attention.
Water expands as it freezes, and the pressure that builds inside a pipe can split it while the contents are still solid. The ice plug then acts as a seal, so nothing leaks.
When the ice melts, the split opens and water flows. That is why a house can come through a cold snap apparently fine and then flood on the afternoon it warms up.
So the checklist runs on the thaw, not on the coldest night. Walk the house as temperatures rise, and again a few hours later.
What should you check after a hard freeze?
Walk every water fixture and look for leaks, weak flow, or no flow, then inspect ceilings, walls, and floors near plumbing for stains or dampness. Check the water heater, washing machine hoses, outdoor spigots, and any unheated space. Know where the main shutoff is before you need it.
The inspection walk
Do this room by room rather than by memory.
Run every faucet, hot and cold. No flow or weak flow suggests a line is still frozen or already failed.
Flush every toilet and check for refill problems.
Look at ceilings and the walls below bathrooms and the kitchen, especially any second-storey plumbing. Stains, sagging, and bubbling paint all indicate water above.
Check under every sink with a flashlight, including the back corners of the cabinet.
Look at the water heater, the connections behind the washing machine, the dishwasher, and the refrigerator supply line.
Check unheated spaces: garage, crawlspace, basement, attic, and any exterior wall with plumbing in it.
Check outdoor spigots and irrigation. A split outdoor spigot often shows up as water inside the wall behind it.
Listen. Running water with everything off is a strong signal, as is a water meter that keeps moving.
Know where the main shutoff valve is and confirm it turns. Finding out during an active leak is the wrong time.
If you find water
Speed matters more than technique in the first hours.
Shut the water off at the main or at the local valve.
Photograph and document everything before moving or cleaning anything, since insurance claims depend on it. What to capture is covered in documenting water damaged items for insurance.
Call a plumber for the pipe itself. Cleaning up around an active leak accomplishes nothing.
Remove standing water and get wet items out of the affected area, lifting furniture off wet flooring.
Start drying immediately. The 24 to 48 hour window is the reason haste beats thoroughness on day one.
Source: EPA guidance on moisture and mold prevention in buildings
Do not use an open flame or a torch to thaw a pipe. This is a common cause of house fires. Use gentle warmth and, if you are unsure, call a plumber.
Small, confined spills on hard surfaces can be handled directly, and the method is in how to dry a small spill before it molds.
Where cleaning ends and restoration begins
This is the distinction that decides how much of the job is yours.
A small amount of clean water on a hard, nonporous surface, dried within hours, is a cleaning task.
Water that soaked into drywall, insulation, subfloor, cabinetry, or framing is a restoration task. Those materials wick moisture upward and inward, and the surface dries long before the interior does. A restoration contractor uses moisture meters and commercial drying equipment to confirm a material is actually dry, which you cannot judge by touch.
Water is also classified by what it contains, and the category changes the handling entirely -- clean supply water is different from water that has passed through building materials, and both are different from sewage. The distinctions are explained in water damage categories explained.
Household fans and a dehumidifier are not equivalent to professional drying equipment, and treating them as such is how a wall stays wet inside for weeks. See why a box fan will not dry a flooded room.
Sewage backup is a separate situation with its own rules and is not a homeowner cleanup.
Call restoration for anything beyond a small confined spill, and call them the same day. Their value is in the first 48 hours.
The cleanup that is yours
Once the water side is handled or handed off, there is real cleaning work.
Hard surfaces that got wet with clean water can be cleaned and dried normally. The general approach after water exposure is in best way to clean after flooding.
Wash textiles that got damp before they develop a smell. Damp fabric left in a pile for two days is a separate problem.
Clean and dry anything that was stored on a wet floor, especially cardboard, which wicks and holds moisture.
Ventilate and dehumidify the space to bring humidity down, since a house that has just released a lot of water into the air will condense it somewhere else.
Watch for a musty smell over the following weeks, which is the first sign that something did not dry.
The non-plumbing freeze cleanup
A hard freeze leaves other work that has nothing to do with pipes.
Salt and de-icer residue tracked indoors is abrasive and hazes floors, and it needs dry removal before any mopping.
Entry mats and boot trays are saturated and need drying or swapping.
Window sills and tracks collect condensation during extreme cold, and that water sits until someone dries it.
Outdoor items brought in to protect them from the freeze arrive with dirt and moisture.
Garage floors take a mix of melt water, brine, and grit.
Check the furnace filter, since the system ran hard through the cold and a loaded filter restricts airflow when you need it most.
Preventing the next one
Freeze prevention is cheap relative to a burst pipe.
Insulate pipes in unheated spaces before the season, not during a cold snap.
Disconnect and drain garden hoses and shut off supply to outdoor spigots.
Open cabinet doors under sinks on exterior walls during extreme cold so warm room air reaches the plumbing.
Let a faucet drip on the coldest nights, particularly on lines running through exterior walls.
Keep the heat on even in an empty house, and never let it drop far during a cold snap.
Label the main shutoff so anyone in the household can find it fast.
FAQ
When do pipes usually burst, during the freeze or the thaw?
Usually during the thaw. Freezing water expands and can split a pipe while the ice plug still seals the break, so nothing leaks until it melts. That makes the hours after temperatures rise back above 32 degrees F the time to walk the house and inspect.
What should you check inside after a hard freeze?
Run every faucet and flush every toilet, then look for stains or dampness on ceilings, walls, and floors near plumbing. Check under sinks, at the water heater, behind the washing machine, at outdoor spigots, and in any unheated garage, crawlspace, or attic.
How fast do you need to dry water after a freeze?
Within about 24 to 48 hours, which is the window commonly cited before microbial growth begins on wet building materials. Speed matters more than thoroughness on the first day, and materials that feel dry on the surface are often still wet inside.
Can you clean up burst pipe damage yourself?
Only if it is small, confined, and on hard nonporous surfaces. Water that soaked into drywall, insulation, subfloor, or cabinetry needs a restoration contractor with moisture meters and commercial drying equipment. Household fans and a dehumidifier will not dry a wall interior.
Is it safe to thaw a frozen pipe yourself?
Gentle warmth applied to an accessible pipe can work, but never use an open flame, a torch, or a propane heater -- this is a frequent cause of house fires. If the pipe is inside a wall or you cannot locate the frozen section, call a plumber.
What should you do first if you find water after a freeze?
Shut off the water, photograph everything for insurance before moving anything, then call a plumber for the pipe and a restoration contractor if anything porous is wet. Start removing standing water immediately, because the drying clock begins the moment the leak does.
A freeze event usually leaves work in several rooms at once, on top of whatever repairs it caused. If you want the cleaning side handled while the trades work, get a quote or read more about house cleaning services.
