Burst pipe disasters are compounded by ongoing (and potentially expensive) problems, including deep structural damage and mold growth. Even a hairline crack in a water pipe can release up to 250 gallons (950 liters) of water a day.
So how do you know if your home's pipes are frozen and creating a disaster just waiting to happen? The answer to this is surprisingly simple: If you turn on the water faucet and water does not come out -- or if you flush a toilet and it does not refill -- your water pipes are probably frozen. Alternatively, if you turn on a faucet full strength and only a trickle is released, this could also be a sign the water pipes are blocked by ice. If you suspect a water pipe is frozen, it's time to call a plumber and turn off the water where the main line enters your home.
Of course, this advice usually only applies to areas in which temperatures have dropped near or below freezing (32 F or 0 C). As a general rule, temperatures below 20 degrees Fahrenheit (minus 7 degrees Celsius) put water in pipes at risk for freezing. However, once the wind chill is factored in, water pipes could potentially freeze above the 20 degree Fahrenheit mark, too.
As the hydrogen and oxygen molecules that make up water begin to transfer their heat to the freezing air around them, they bind more tightly. If the pattern of the hydrogen and oxygen molecules remained unchanged, all this huddling would result in solid, frozen matter that would actually take up less space than the liquid form. But water just has to be different. Instead, the pattern of its molecules changes as it freezes, taking up more space and expanding as it turns into ice.
And when it comes to the water pipes in your home, this expansion of water as it freezes can put a lot of stress on stiff metal and plastic pipes, as well as pipe joints. Take note, inventors: If water pipes were made out of an expandable material, freezing water wouldn't affect their performance and would eliminate damage to thousands of homes each year.
So this means that when water expands into ice it causes pipes to burst, right? Not directly. Instead, the problem occurs when a pipe becomes blocked by ice, often in multiple locations within the pipe. These blockages -- located between the water source and the closed faucet -- cause a buildup in water pressure. Upstream from the ice blockage, the water can retreat back to the source without pressure buildup. Downstream from the ice blockage, the water is trapped between the blockage and the closed faucet. If more ice forms, it has nowhere to go and the pipe will burst. Pipe joints are particularly susceptible to leaks, but cracks can occur along other sections of a pipe, too.
This is one reason why it's a good idea to leave a faucet slightly open if you're worried your pipes may freeze. Some people think the constant drip keeps the water from freezing but actually water can freeze while even flowing. The real benefit is relieving the pressure.
Although pipes will burst or begin to leak as they thaw, leading some to believe the melting process causes problems, that's not the case. The actual damage will have occurred days earlier when the pipes became frozen; you simply won't know how much damage was done until the thaw begins because the ice blockage had been acting as a plug.
In colder regions of the U.S., most homes are built so the water pipes are protected from the elements. Insulated water pipes are placed in heated, interior areas of a home, steering clear of unheated attics, crawl spaces and exterior walls. In warmer regions of the U.S., homeowners aren't always as fortunate. Freezing is rare, which leads to less attention to water pipe insulation and placement during construction. During a cold snap, this could translate into a frozen -- and then watery -- mess.
What's the best way to prevent frozen water pipes, wherever you live?
If you're right in the middle of a cold snap, there are few additional precautions you can take, too.