Pool pumps move pool water through its filtration system and back to keep chemicals at proper levels and bacteria growth to a minimum. If a pool pump runs dry, the entire pool water system suffers.
Pool pumps run dry for a variety of reasons, but two particular causes are common and easily avoided. If the water level of the pool is too low, the pump cannot pull in the water efficiently or at all. Also, the pool's pump basket can get obstructed, causing water flow to ease or stop altogether.
If a pool pump runs dry, turn the device off immediately until the cause is determined. If a pool pump runs without water, it can overheat and require overall replacement.
Check the pool's water level, as well as the pump basket for any clogs. Examine the pool pump itself for any cracks that may allow air to penetrate within, taking up the area meant for the pool water.