Shutoff assembly

A shutoff assembly includes a main body, a drain cover, a plugging device, and a shutoff cap. The plugging device is disposed in a through hole of the main body and connected to a drain opening coupler. A sliding path is formed in a side recessed slot on the plugging device for a hook lever to slide through. A spring is disposed between the shutoff cap and the plugging device. The drain cover is placed below the top portion of the main body. When the shutoff assembly is pressed, the bottom end of the hook lever is trapped in a bottom recess and the drain cover blocks the drain hole of the drain opening coupler. When the shutoff assembly is pressed again, the hook lever is released and the drain cover is moved up to open the drain hole.