Pool Main Drains are an added accessory to any swimming pool.Therefore, no pool needs to have a main drain. However, they can help the circulation of your pool and drain the necessary water in the fall with ease. First, two drains will be teed off of each other, with a minimal three feet of separation. They also come equipped with an antivortex cover for safety. Adding a main drain to your pool will add an additional 500-600 dollars to the install price. It is also important to have them be properly winterized every winter.