This Architectural Drawing is AutoCAD 2d drawing of Toilet flush tank details in AutoCAD, dwg file. A toilet flush tank holds a supply of water to flush out the sewer. It releases this water or sewage periodically and fills once the tank is empty. A flush tank is a reservoir that contains water, sewage or some other type of fluid. The fluid in the flush tank is released during periodic intervals to clean equipment or to clean the tank itself. Flush tanks typically hold enough liquid to completely cleanse whatever it is meant to flush.