When the water freezes, it eventually expands in volume by about 9 percent. And that too with tremendous force: So, the pressure inside the pipes go from 40 pounds per square inch to 40,000 pounds per square inch. Oopss… And, no pipe can hold that much pressure, so it breaks open. The break may occur at the place where the ice forms. But, often, it happens where the water pressure finds a weak spot in the pipe. It may be inches or even feet from the frozen area. So it’s better to check your pipes in winter.