What Is an Anti-Vortex Pool Drain? An anti-vortex pool drain is a specially designed drain cover used in swimming pools and spas to reduce suction force and prevent dangerous entrapment incidents. Unlike older flat or domed drain covers, anti-vortex designs disrupt the formation of a whirlpool, significantly reducing the risk of a swimmer being held underwater by suction. These drains are now considered a critical life-safety component in residential and commercial pools. W