A toilet tank is a crucial component of a flush toilet, responsible for storing water used during flushing. It is typically located at the back of the toilet bowl and is filled with water after each flush. The tank contains various parts, including a float, fill valve, and flush valve, which work together to control the water flow and ensure efficient flushing. When the toilet is flushed, the flush valve opens, allowing water to rush from the tank into the bowl. This action creates a siphoning effect that removes waste from the bowl. After flushing, the fill valve refills the tank with water, preparing it for the next use. Proper maintenance of the toilet tank is essential for optimal performance and water conservation.