Leaks are often signs of bigger problems with the pipes, and they can be hard to find because they are out of sight. A plumbing emergency caused by a water leak will depend on how big the leak is, which will tell you how quickly you need to fix it.  If there are water stains on the walls or ceiling, it could mean that there is a problem with the pipes that run through the walls or ceiling. Leaks can also happen when the water pressure changes in different parts of the plumbing, when limescale builds up in the pipes, or when the pipes rust.