Purpose of this paper is to find the solution of cleaning the household water tank used for water storage. The work is done by using two different mechanisms (a)Pinion-Rack system (b)Four Bar Linkage system. In Pinion-Rack method we use a motor and connect it to a Rack. A shaft is connected to the motor and a four-bar linkage is joined to it. For cleaning the walls of the overhead tank we make use of PVC made brushes and attach them to the ends of four bar linkage and for cleaning the floor we join a circular disc to the bottom end of the shaft. The disc has some thickness. The bottom and the periphery of the disc is covered with PVC brushes. This setup is designed , such that it can fit itself according to the diameter of the water tank. When this whole setup is placed inside the cylindrical overhead water tank and switched on, the motor starts to rotate the shaft, the disc and four bar linkages. The Brushes are moved up and down by making use of pinion-rack mechanism.Thus cleaning operation is performed. The society is tending towards automation day by day, cleaning the tank manually is undesirable as it requires lots of time and efforts. So, to solve this problem, this household water tank cleaning system is developed that is more efficient , more safe, less time consumption and of course no extra human efforts. It doesn't affect the environment and human health in any way. Here a rod having grooves is placed in which brushes are attached through two arms. For rotation of the arms we connect a DC gear motor and a AC motor to main rod. The system also consists of microcontroller and relays for controlling purposes.