This term usually refers to a plumbing fitting installed on the suction side of the pump in pools, spas and hot tubs. Sometimes called the main drain, it is located in the deepest part of the pool, spa or hot tub. It is not a drain, such as a drain on a kitchen sink. Main drains do not allow the to drain to waste but rather connect to the pump for circulation and filtration.
The quantity of water flowing past a designated point within a specified time, such as the number of gallons flowing past a point in 1 minute – abbreviated as gpm.
