Abstract: A shaft position recorder apparatus and method are described which can be used for recording changes in liquid levels. The recorder employs an electronic memory for storing the changes in liquid levels which are entered into the memory at predetermined time intervals if they exceed a predetermined magnitude or "deadband". The recorder apparatus employs a shaft position encoder as an input means for supplying a group of pulses for each measured change in shaft position or liquid level so that the sequence of the pulses indicates whether the change was an increase or decrease from the previous reading. The preferred shaft encoder includes three reed switches which are operated by four permanent magnets mounted on a support disk which rotates in accordance with the position of the shaft, such shaft being coupled to a float pulley when used as a liquid level recorder.