For wells with a depth of 40 meters in China, it is generally recommended that the agitator length be about 30 meters. This is because the length of the agitator should be able to cover the bottom of the well with a certain margin. At the same time, although the long agitator can cover the bottom of the well, it will also increase the power and power consumption of the driving device, which is not conducive to energy saving and environmental protection. Therefore, generally speaking, it is more appropriate to use a stirrer with a length of about 30 meters for a household 40-meter well. Of course, the specific choice should also consider factors such as model, power and frequency of use. It is recommended that you consult relevant professionals or manufacturers before purchasing, so as to choose the agitator that best suits your needs.