Backwashing is a process used to clean filters in swimming pools, aquariums, and water treatment systems. During backwashing, water is reversed through the filter, dislodging trapped dirt and debris. This helps maintain the filter's efficiency and ensures clean water circulation. The backwashing process typically involves turning a valve to change the water flow direction. The dirty water is then expelled through a waste line, allowing fresh water to flow through the filter afterward. Regular backwashing is essential for maintaining the performance of filters and prolonging their lifespan.