How a Pool Main Drain Works


Many localities and homes nowadays have a pool. Cleaning a pool can be quite a bit of work, so this is where a pool main drain comes in. A pool main drain a drainage facility situated at the lowest point of the pool. There can be more than one main drain situated in a swimming pool. A main drain’s job is to suck out all the dirt and debris, which accumulates at bottom of a pool. A main drain generally consists of an access hatch, a floating weir, strainer basket, equalizer line, suction line and anti-vortex chamber.

How a main drain works?

  • As swimming pools are built in a slanting manner all dirt and debris accumulated goes towards the access hatch located at bottom most part of a pool.
  • Next it passes through a floating weir where it allows small amounts of water to pass at a time.
  • Then the water containing debris and dirt passes through a strainer basket. There any large debris such as twigs, leafs, etc. is collected.
  • Next comes an equalizer line whose job is to keep away water from entering the pump system.
  • This process of cleaning the pool requires a lot of suction power. So a separate pipeline, which is the suction line, is connected to a suction machine at one end and a strainer basket at the other.
  • One of the most important parts of a main drain system for safety is an anti-vortex cover. This is connected to the equalizer line, which makes sure no dangerous vortex is created.


A main drain system helps in efficient cleaning of the pool. One does not need to be worried about cleaning all the dirt and debris located at the bottom of the pool. People don’t even have to worry about emptying the water in the pool to clean it


The major disadvantage of having a main drain in a pool is that if the anti- vortex cover is not installed properly, vortex may be created in the pool. This is quite dangerous as many people have been severely injured and many even died due to drowning.

Now you know what a main drain system is and how important it is in maintaining hygiene of a pool. It continuously cleans the dirt and debris collected at the bottom of the pool. The builder should have installed a main drain in your pool when it was built. Make sure he includes an anti-vortex cover, for safety. For issues with main drain contact your local plumber.