A bad water pump can make a rubbing, grinding or whining sound. A water pump is relatively silent when it is operating properly. If it makes any loud noises, it is an indication that the bearings are going out.
Another indication of bearing failure is coolant leaking from the water pump. The seals in water pumps are designed to leak when the bearings go out. Drops of coolant on the ground under a parked car can be the first sign that a water pump is beginning to fail.
Auto repair shops routinely replace water pumps. However, instructions for water pump replacement are available at About.com.