Automatic water level controller for both overhead and underground tank is designed to monitor the level of water in a tank. It displays the level of water and when it is at the lowest level; a pump is activated automatically to refill the tank. When the tank is filled to its maximum capacity, the pump is automatically de-energized. Several circuits are put together to ensure proper working of this design, and the block diagram includes the supply unit, the micro-processor unit, the sensor unit, the display unit and the pump drives unit. The power unit is responsible for turning on the entire circuit. Some components are used to set up power unit and they include; a 15v step down transformer, a bridge rectifier circuit, a smoothening capacitor and a voltage regulator IC. The microprocessor (AT89S50) controls virtually all the actions carried out in this design. (AT89S50) is used in the design. The sensor unit is responsible for sensing the level of water and transfer the current position of water to the microprocessor. The display unit in the circuit is use to physically show the current position of water in the tank, the properties of seven segment display are been used.