Key takeaways
- Pipes freeze where cold air reaches them: exterior walls, crawl spaces, garages, basement rims and hose bibs.
- Disconnect hoses and shut off and drain outdoor spigots before the first hard freeze.
- Insulation slows freezing but does not add heat. Keep the house heated and open cabinet doors during a cold snap.
- Thaw a frozen pipe slowly with warm air, never with a flame, and shut off the main if you find a split.
Why pipes freeze and where
Water freezes at 32°F, but a pipe inside a house does not freeze the moment the air outside drops that low. It takes sustained cold, often with wind, to pull enough heat out of a pipe in an exposed spot. Ohio gets that kind of stretch most winters, so it is worth preparing even if you have never had a problem.
When water turns to ice it expands and puts pressure on the pipe. Often the split forms not where the ice is but in the section between the ice and a closed faucet, where the trapped water has nowhere to go. That is why a burst pipe often announces itself only after the ice melts and water starts flowing.
The usual vulnerable spots are easy to list:
- Pipes in exterior walls, especially a kitchen or bathroom sink on an outside wall
- Pipes in unheated crawl spaces, attics and garages
- Lines along the basement rim, where the house sits on the foundation
- Outdoor hose bibs and any irrigation lines
- Pipes near a loose window, a dryer vent or a gap where cables enter the house
Older homes in the region often have plumbing that was added or rerouted over the years, sometimes through spaces that were never meant to carry water lines. If you see a pipe running through an unheated corner, it deserves attention.
Before the cold arrives
The fall is the time to do the work, before a forecast gives you a deadline.
Hose bibs. Disconnect every garden hose, since a hose left attached traps water in the spigot. Many newer homes have frost-free hose bibs, which have a long stem that puts the shutoff inside the heated wall. They only work if the hose is removed and the spigot slopes slightly downward so it drains. Older homes may have a plain spigot with a shutoff valve inside. Close that valve, open the outdoor spigot, and let it drain. If you cannot find or turn the inside valve, a plumber can add one.
Insulation. Foam sleeves are inexpensive and fit on exposed pipes in basements, garages and crawl spaces. Insulate the hot and cold lines. Remember that insulation slows heat loss; it does not make heat. A pipe in a truly cold space can still freeze, just later.
Air leaks. Seal gaps where pipes and cables pass through walls with caulk or foam. A small draft can aim a stream of cold air right at a pipe.
Irrigation. Lawn sprinkler systems should be drained or blown out before winter. Leftover water in the lines is a frequent source of split pipe and cracked backflow devices.
Heat cable. Electric heat cable made for pipes can help in a problem spot, but use only products listed for plumbing, follow the instructions exactly, and never overlap the cable. If you are unsure, ask a plumber.
During a hard freeze
When the forecast turns severe, a few habits help.
- Keep the heat on. Set the thermostat to a normal temperature, and if you travel, do not set it below the mid-50s °F. Turning heat off to save energy is how many freezes begin.
- Open cabinet doors under sinks on exterior walls so room air reaches the pipes.
- Let a faucet drip. Choose a faucet on a vulnerable line, often the one farthest from where water enters the house, and let a thin steady stream run. Moving water is harder to freeze, and a drip relieves pressure if ice starts to form.
- Close the garage door and any basement or crawl space access that is open.
- Know your main shutoff. If you leave for several days in winter, ask a plumber about shutting off and draining the system.
A hairline of frost on a pipe, no water, or only a trickle from a faucet when the rest of the house is fine are signs of a freeze in progress.
If a pipe freezes
Start by finding the frozen section. Open the faucet served by the pipe so water and steam have a path out as it thaws. Then apply gentle heat, beginning near the faucet and working back toward the frozen area. A hair dryer, a heating pad or towels soaked in warm water all work. Keep any electrical device well away from standing water.
Do not use a propane torch, a kerosene heater, or any open flame. These start house fires and can overheat a pipe or burn its soldered joints. Do not use a space heater near water or in a way that could tip over.
If you see water, a bulge or a crack, shut off the main right away and call a plumber. Do not thaw a split pipe, because it will begin to leak as the ice melts. If the frozen section is behind a wall or ceiling and you cannot reach it, raise the heat in the house, open cabinet doors, and call a plumber instead of cutting into the wall yourself.
Once the water is running again, check the pipe and joints a few hours later for any leak that the ice was holding back.
When a plumber should look at it
A pipe that froze once will probably freeze again. Call a plumber if the same line freezes every cold snap. The fix might be rerouting the pipe, adding insulation inside a wall, or sealing the opening that is letting cold air in. A plumber can also check pipes for damage after a thaw, since a split may be small enough to seep for weeks.
If water is flowing where it should not be, see leak repair. If you want help with a hose bib shutoff or a problem spot, reach out. For the bigger picture on leaks, shutoffs and pressure, read the main guide.
Frequently asked questions
At what temperature do pipes freeze?
Water freezes at 32°F, but pipes inside a home usually need hours of cold below that, and wind makes it worse. Pipes in exterior walls, garages and crawl spaces are the first to go.
Does letting a faucet drip really help?
It helps on vulnerable lines. Moving water is harder to freeze, and a drip relieves pressure between ice and the faucet. It works best alongside insulation and a heated house, not instead of them.
What should I do if I think a pipe has burst?
Shut off the main water valve, open a faucet low in the house to drain the lines, and call a plumber. If water is near electrical outlets or the panel, stay clear and turn off power only if you can do so safely.
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