Burst Pipe: What to Do in the First Hour, and What Comes Next

A supply pipe is under pressure day and night, so a split keeps pouring until someone closes a valve. The damage keeps growing after the water stops, too: the EPA says water-damaged areas and items need to be dried within 24 to 48 hours to prevent mold.

If a pipe is frozen but hasn't leaked yet, start with frozen pipes: what to do. If the water is coming from the water heater itself, see water heater leaking.

Most Likely Causes

1. Freezing. The classic winter burst: ice blocks the pipe, pressure builds, and the pipe splits in a cold spot such as an exterior wall, crawl space, attic, or unheated garage. The leak often starts hours later, as the ice melts. If other faucets were trickling too, more pipes may be frozen or split; tell the plumber, and see the frozen pipes guide before thawing anything.
2. A failed supply hose or connector. Not every burst pipe is a pipe. The flexible lines to the washer, dishwasher, toilets, faucets, and ice maker fail too, and IBHS notes their fittings, especially rubber gaskets, degrade over time. Water from behind or under one fixture is the giveaway.
3. Age and corrosion. Copper can develop pinhole leaks from pitting corrosion, which EPA research links to water chemistry, though the exact cause isn't settled, and older galvanized steel pipe rusts from the inside. One pinhole on an old system may not be the only weak spot, so ask the plumber to check the rest.
4. Water pressure that is too high. Zurn Wilkins, a regulator maker, notes that codes require a pressure reducing valve when street pressure is above 80 psi, and that long-term excess pressure can break plumbing components and cause flooding. A plumber can measure the pressure and check or install the regulator.
5. Water hammer. A bang in the walls when a faucet or the washer's valve shuts off. Oatey, which makes hammer arrestors, warns that its repeated force can blow apart weak joints. A plumber fixes it by securing loose pipes and adding arrestors.
6. Physical damage. A nail or screw driven through a pipe in a wall, a pipe crushed in a crawl space, or a line pulled loose when an appliance was moved.

What You Can Fix Yourself

Stop the leak until the plumber comes

• Isolate it if you can. If the leak is on one fixture's supply line and that fixture has its own shutoff valve, close it. If it holds, reopen the main slowly so the rest of the house has water.
• Replace a burst supply hose or connector. A split washer hose or a failed sink or toilet supply line is a part, not a pipe: with its valve closed, a new line of the same size and type is a homeowner job. Open the valve slowly afterward and watch for drips.
• Leave the pipe itself to the plumber. Hardware stores sell repair clamps and push-fit couplings, but the right fitting depends on the pipe's material and size, a freeze split often runs longer than it looks, and a stopgap that lets go overnight is a second flood. Keep the main closed until the repair is made, and if the plumber can't come soon, ask whether a temporary repair is safe for your pipe.

Limit the water damage

1. Photograph first: the break, the water, and everything that got wet, before you move or clean anything. The Insurance Information Institute's order is the same: document the damage, then take reasonable steps to prevent further damage.
2. Move what you can save into a dry room. Keep damaged belongings, if you can, until the insurance adjuster has seen them.
3. Remove standing water with a mop, towels, and a wet/dry vac; our wet/dry vac guide covers choosing one. Use the vac only where the water isn't touching outlets or cords, plug it into a GFCI-protected outlet in a dry spot, and don't handle the plug with wet hands.
4. Dry the room. Run fans, pull up wet area rugs, and open cabinet doors on the wet wall. The EPA's rule for lowering indoor moisture: ventilate when the outside air is cold and dry, and run a dehumidifier when it is warm and humid.

If you can't get everything dry within 24 to 48 hours, the American Red Cross says to assume you have mold growth. Soaked drywall, insulation, carpet pad, and subflooring usually need a restoration company.

Stay safe while you clean up

• Electricity. Don't use any appliance, cord, or outlet that got wet. The CDC says equipment must be completely dry before it goes back into service, and power should stay off until a qualified electrician has inspected it. CenterPoint Energy warns that a submerged outlet, cord, or appliance can energize the water around it.
• Ceilings. The Red Cross and FEMA flood repair guide warns that a sagging ceiling may be holding water and that wet plaster or wallboard is dangerous if it falls. Stand away from it, never under it, and let the pros drain it.
• Mold. The EPA says a homeowner can usually clean a moldy patch under about 10 square feet, wearing an N-95 respirator, long gloves, and goggles without vent holes; for more, call a professional. Ready.gov says people with asthma, other lung conditions, or weakened immunity should not enter buildings with indoor water leaks or mold that can be seen or smelled.

Document it for your insurer

Call your insurer the same day. The Insurance Information Institute says your policy spells out your responsibilities, and suggests asking whether you are covered, how long you have to file, and whether the loss will exceed your deductible. Keep the photos, a list of damaged items, and every receipt, and ask the plumber to save the burst section of pipe. If wet drywall or carpet has to come out before the adjuster visits, photograph it first.

When to Call a Pro

A plumber, for every burst pipe: the repair, a leak you can't find, a main shutoff that stuck or didn't fully close (have it replaced), and a look at why it burst, including a pressure check.

A water damage restoration company, when water has soaked into drywall, insulation, carpet pad, subflooring, or a ceiling; when you can't dry it within 24 to 48 hours; when the water was contaminated; or when mold covers more than about 10 square feet. They remove the water and confirm the structure is dry with moisture meters, which the EPA notes can monitor drying. They don't fix the pipe: the ANSI/IICRC S500 water damage standard leaves finding and correcting the source to the property owner, which means your plumber. Your insurer may be able to recommend a company.

An electrician, if water reached the panel, outlets, wiring, or light fixtures. Leave that power off until they have checked it.

Prevent It

• Test your main shutoff once a year, and have a plumber replace it if it is stuck.
• Keep pipes from freezing. Insulate pipes in unheated spaces, keep the heat no lower than 55°F when you're away, and let faucets on exposed runs drip in hard freezes; the frozen pipes guide has the details, and our heat tape guide covers heat cable, installed exactly as its maker specifies, for pipes insulation alone can't protect.
• Replace supply hoses on a schedule. IBHS says to change washer and dishwasher hoses more than 10 years old; the Insurance Information Institute says to check appliance hoses yearly and replace them all every five to seven years.
• Have a plumber check the water pressure if pipes bang, the pressure seems strong, or it has never been checked.
• Put leak sensors where water shows up first: under sinks, behind the washer, and beside the water heater. One with phone alerts reaches you while you're away; our leak detector guide compares them. For a house that often sits empty, a plumber can add an automatic shutoff valve on the main that closes when a sensor trips.

Frequently Asked Questions

How do I know if a pipe burst inside a wall?

Look for a stain or bulge on drywall or a ceiling, peeling paint, a musty smell, running water when nothing is on, or a jump in the water bill. The EPA's WaterSense meter test confirms a leak: read the water meter, use no water for two hours, and read it again. If it changed at all, you probably have a leak. Close the main and call a plumber.

Can I turn the water back on before the plumber comes?

Only if the break is isolated: the leaking line has its own shutoff valve, you have closed it, and it holds. Otherwise keep the main closed until the pipe is repaired.

Will my insurance pay for a burst pipe?

That depends on your policy and on what caused the burst, and only your insurer can tell you. Read the policy before you need it. IBHS also suggests keeping a video inventory of your belongings in the cloud so a claim is easier to itemize.

The Bottom Line

Close the main, stay out of water that could be touching electricity, drain the lines, and turn off the water heater if the water will stay off. Then photograph everything, get the water out, and dry the house within 24 to 48 hours. Call a plumber, your insurer, and, if water soaked into walls, floors, or ceilings, a restoration company. Then fix the cause, and put leak sensors where the next leak would start.

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