Abstract: The disclosure is directed to a cistern system which enables maintenance, removal, or adjustment of various components through a maintenance window according to some embodiments. In some embodiments, the cistern system includes screen support members that cooperate with a flush valve to remove fallen components. In some embodiments, the cistern system includes a frame with an adjustable upper bar that can be removed to facilitate the installation of various components. In some embodiments, the frame includes a bar holder fastener that enables vertical leveling when the frame is secured to a wall with one or more wall mounts. In some embodiments, the frame includes adjustable frame supports that can be fixed in position by frame height adjusters when only supporting the weight of the cistern system but can be adjusted in and out of the frame by adding additional downward force to the frame.