The purpose of packing is to:

The purpose of packing in a pump system is primarily to control water leakage along the pump's shaft. Packing is a sealing material used around the shaft, and its main function is to create a tight seal that minimizes the amount of fluid that escapes from the pump as it rotates. This is crucial in ensuring that the pump operates efficiently and maintains proper pressure within the system. By effectively controlling leakage, packing helps to reduce waste, prevent damage to the pump, and maintain the overall integrity of the pumping system.

While packing may provide some level of support to the shaft and can play a role in lubrication under certain conditions, the core function remains focused on sealing and controlling fluid leakage. Other options pertain to different aspects of pump design and operation, but managing water leakage is the primary role of packing.