The height of self suction is called suction lift. The unit is generally meters.

Also known as maximum self suction height. The maximum height at which the pump can automatically draw water up without adding water (the vertical distance between the pump suction port and the liquid level to be pumped). Our water pumps are all self priming pumps, and the indicated suction head refers to this situation. Some centrifugal water pumps do not have self suction capacity, and the first use requires additional water supply. Some diaphragm water pumps may also have self suction capacity, but the standard suction head often differs from the vertical height at which water can be extracted from the inlet pipe, which is entirely under air. Please note this.

The height of the suction head is related to the power, flow rate, structure, etc. of the pump, but is limited by volume and power. Generally, the self suction suction head of a micro water pump is not easy to achieve a higher height because one atmospheric pressure can raise the water pressure by up to 10.3 meters (because one atmospheric pressure ≈ 10.3 meters of water column produces pressure), so the maximum self suction head is only about 10.3 meters. However, in practical operation, due to sealing performance reasons, the suction head generally does not exceed 6.5 meters.