Why Pipes Freeze and Burst
When water in a pipe freezes, it expands by about 9 percent by volume. In a rigid pipe, this expansion creates pressure that can exceed 2,000 PSI -- far more than any pipe can withstand. The burst often occurs when the ice thaws and water flows again into the compromised section. Pipes most at risk are those in unheated spaces: exterior walls, attics, crawl spaces, unheated garages, and vacation homes that lose heat.
Prevention Steps Before Cold Weather
Key prevention measures: insulate pipes in unheated spaces with foam pipe insulation or heat tape, seal air leaks near pipes (gaps around pipes where they enter through exterior walls), disconnect and drain outdoor hoses and shut off the supply valve to outdoor hose bibs, know where your main water shutoff is located, keep garage doors closed if water supply lines run through the garage, open cabinet doors under kitchen and bathroom sinks on exterior walls during freezes, and maintain home heating at 55 degrees minimum even when away.
During a Freeze Event
During periods of extreme cold, let cold-water taps on exterior walls drip slowly -- moving water requires lower temperatures to freeze. Open cabinet doors under sinks on exterior walls. Monitor your water pressure. If water stops flowing from a faucet, a pipe may be starting to freeze. Keep heat on throughout the home, not just in occupied rooms.
If a Pipe Bursts
Shut off the main water supply immediately -- know where this valve is before an emergency. Turn off electricity in the affected area at the breaker box. Call a plumber and a water damage restoration company. Document all damage with photos before cleanup begins. Do not use electrical appliances in wet areas. The water damage from burst pipes requires professional extraction and drying to prevent mold.
Vacation and Seasonal Homes
Seasonal and vacation homes are at particularly high risk because they may be unoccupied when a freeze event occurs. Preventive measures include: draining the water system completely when closing for winter, installing a whole-home water shutoff with a leak detection system, using a temperature monitoring system that alerts you when indoor temperature drops below safe levels, and ensuring someone can check on the property during extended cold periods.
Frequently Asked Questions
Does homeowners insurance cover burst pipes from freezing?
Yes, in most cases. Burst pipes from freezing are covered as sudden and accidental water damage under standard homeowners policies. However, insurance may deny coverage if the homeowner failed to maintain adequate heat in the home -- most policies require maintaining heat at a minimum temperature. Verify your policy requirements.
At what temperature do pipes freeze?
Pipes can begin to freeze when outdoor temperatures drop below 20 degrees Fahrenheit and pipes are exposed to those temperatures. Pipes in unheated attics, crawl spaces, and exterior walls reach dangerous temperatures before interior pipes do. In homes built for warm climates, pipes may be closer to exterior walls and more vulnerable.
How much water damage can a burst pipe cause?
A single burst pipe can release hundreds of gallons per hour. A 1/8-inch crack in a pipe releases 250 gallons per day. Burst pipes that go undetected for hours or days can cause tens of thousands of dollars in water damage. Automatic water shut-off devices that detect abnormal flow can limit damage dramatically.
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