Anytime the temperature outside drops below 32 degrees Fahrenheit, the water inside the pipes starts expanding, which may cause the pipes to burst. Pipes or hoses that are located outside, in unheated areas of the house or along exterior walls without sufficient insulation are most likely to freeze and burst.
Some ways to prevent the pipes or hoses from bursting are to bring the hoses out of the cold, let the faucets slowly drip water, open cabinet doors to allow heat to get to the pipes underneath, and add insulation around pipes that are exposed to the cold temperatures. Other methods include burying them where possible.House or along exterior walls without sufficient insulation are most likely to freeze.
The more exposed your pipes are to the elements, the more likely they are to freeze. If you are able to re-route pipes so they run through basements or attics rather than outside, you prevent a lot of freezing. In addition, use pipe sleeves or heat tape to wrap your pipes securely, adding a layer of insulation between your pipes and the freezing weather.
Water left in hoses and sprinkler lines is the first to freeze when winter hits. Drain all your hoses, coil them up and move them inside so they don't crack in the cold. Turn off the hose valve from inside the house if you are able, and open the outside hose tap to let all stored-up water drain out completely. Follow the manufacturers' directions to drain water from your pool and lawn sprinkler systems.
If water is flowing through the pipes, they stand a better chance of making it through a cold snap unscathed. Turn your water on overnight, and let a tiny trickle escape. It's okay to use a pipe that opens to the outside for
In a word, the reason for pipes freeze is low temperature.