Pipes typically start to freeze when outdoor temperatures fall to around 20°F (-6.6°C) or lower, though several factors can influence this. Interior pipes are less at risk than exterior ones, and the level of insulation, whether the water is moving, and how long temperatures stay below freezing all matter. Key points

• Water begins freezing at 32°F (0°C), but pipes generally freeze when ambient temperatures reach about 20°F (-6.6°C) or lower, especially if uninsulated or in unheated spaces.

• Exterior or poorly insulated pipes are the most vulnerable and can freeze after only a few hours in freezing temperatures; interior pipes inside exterior walls can also freeze if those walls are cold or uninsulated.

• Movement helps resist freezing; still water freezes faster than flowing water. Small, uninsulated pipes can freeze more quickly (potentially within a few hours) than larger, well-insulated ones.

Practical tips to reduce risk

• Keep the home heated to at least 65°F (18°C) in cold weather to maintain warmer wall cavities where pipes reside.

• Let faucets drip slowly in particularly cold conditions to relieve pressure and reduce the chance of a burst if a pipe does freeze.

• Insulate exposed and unheated pipes, especially those on exterior walls or in garages, crawl spaces, and basements.

• Open cabinet doors beneath sinks on exterior walls to allow warmer room air to circulate around pipes.

If a pipe does freeze

• Turn off the main water supply if you suspect a burst or a frozen pipe is blocked.

• Apply gentle heat (hair dryer, warm towels, or a space heater) to the frozen section, starting at the faucet end and moving toward the coldest area. Do not use open flames.

• If you can't locate or thaw the pipe safely, contact a licensed plumber promptly.

If you’d like, I can tailor these guidelines to your location, the locations of pipes in your home, and provide a quick checklist for winterizing now.