In the measurement of the depth of underground deep-water wells, the self-made water level measuring instrument of Qilu Water Supply and Drainage Plant has been measured accurately in practical applications and has achieved good results. Currently, it has been promoted and used in this plant.

Due to the fact that the water level in deep wells is below 50 to 60 meters from the ground, the borehole wall is more uneven. Manual measurement with a measuring rope hanging buoy falling into the water, measuring the rope to determine the water level. However, the buoys entering the water need to be judged by personal experience. The pontoon is easy to dock on the surface of the surface of the well and the measurement is inaccurate. In the second half of July, employees of the second water supply plant of the plant tied parallel wires to the measuring ropes and placed weights in the wells. The resistance of the wire not entering the water is infinite, and the contact with the water surface forms a path, and the resistance becomes 2 to 3 ohms, and the metering rope can measure the accurate water level.