The short answer
The Freezing Threshold
Water freezes at 32 degrees Fahrenheit, but pipes usually need sustained cold to actually freeze. The risk climbs significantly once the outdoor temperature stays below 20 degrees for several hours. At that point, water inside pipes can turn to ice, expand, and put pressure on the pipe walls.
The exact temperature that causes a pipe to freeze depends on several factors. How long the cold lasts, whether the pipe is indoors or outdoors, and how much insulation surrounds it all matter. A pipe in an unheated garage or crawl space can freeze faster than one inside a heated wall.
Why Pipes Burst
When water freezes, it expands by about nine percent. That expansion pushes against the inside of the pipe, creating pressure that can crack metal or split plastic. The crack may not show until the ice thaws and water starts flowing again.
Even a small crack can release hundreds of gallons of water in a short time, leading to soaked drywall, flooring, and belongings. That is why a frozen pipe often turns into a bigger water damage issue. Knowing the risk helps you take steps before temperatures drop.
- Pipes in attics or crawl spaces are more exposed to cold
- Exterior walls and unheated garages raise freeze risk
- Moving water resists freezing better than still water
- Insulation or heat tape slows heat loss
- Dripping faucets can relieve pressure buildup
- Shut off outdoor spigots before winter sets in
How to Protect Your Pipes
You can reduce the chance of freezing with a few simple steps. Insulate exposed pipes with foam sleeves or wrapping. Seal gaps around windows, doors, and foundation vents where cold air can reach pipes. On very cold nights, open cabinet doors under sinks to let warm air circulate.
Keep your thermostat set to the same temperature day and night during cold snaps. If you plan to be away, set the heat no lower than 55 degrees. Draining outdoor lines and disconnecting garden hoses also removes water that could freeze and damage the valve.
What to Do If a Pipe Freezes
If a pipe freezes, turn off the water at the main shutoff valve first. Open the faucet nearest the frozen section to relieve pressure as the ice thaws. Use a hairdryer or space heater to warm the pipe slowly, starting from the faucet end. Never use an open flame.
If you cannot thaw the pipe or if you notice a leak, shut off the water and call for help. A plumber can handle the pipe repair. If water has already damaged walls, flooring, or belongings, local water damage pros can handle the cleanup and drying.
- Locate your main shutoff valve before an emergency
- Keep a hairdryer and towels handy for minor freezes
- Check for cracks after thawing, even if no leak is visible
- Document any damage for your insurance records
- Dry wet areas within 24 to 48 hours to limit mold
- If you live in a hot, dry climate like Mesa, note where your shutoff valve is
When to Call for Help
Some frozen pipes are simple to handle on your own, especially if you catch them early. But if a pipe has already burst, you face a larger problem. Water can soak into drywall, carpet, and wood framing, creating conditions for mold and structural issues.
In that situation, you might need more than a plumber. Water damage pros can remove soaked materials, dry the area, and help prevent secondary damage. If you have insurance, check your policy to understand what is covered. Policies vary, and your insurer decides what is covered.
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Call Now (480) 898-4279Frequently asked questions
At what temperature do pipes freeze in an unheated garage?
Pipes in an unheated garage can freeze when outdoor temperatures drop into the 20s, especially if the garage is not insulated. The risk increases if the pipe is against an exterior wall or exposed to drafts. Insulating garage pipes and keeping the garage door closed helps.
How long does it take for pipes to freeze?
It depends on the temperature and pipe location. At 20 degrees, exposed pipes may freeze in a few hours. At 10 degrees or below, freezing can happen faster. Pipes in heated spaces may never freeze, while those in unheated areas can freeze overnight.
Should I let my faucets drip to prevent freezing?
Letting a faucet drip can help, because moving water is less likely to freeze. A slow drip relieves pressure if ice does form, reducing the chance of a burst. Focus on faucets farthest from the main supply, as those pipes are most at risk.