The pump must give a pressure that is the sum of three factors: the geometric height, the pressure drops and the spearhead.
The geometric height is the height difference from the point where the pump is located to the drain point. If the fluid is to rise, it will be positive; but if the drain point is lower, the value will be negative. This is because gravity will help, and the pump will cost less to do the work.
The pressure drop is caused by the friction between the fluid and various elements of the installation itself, such as filters or valves. This loss will depend on the flow rate, the diameter of the pipes and the material with which they are made. Therefore, depending on the type of installation, there will be rules that determine the minimum and maximum flow rates that can be supported.
Finally, the spearhead refers to the pressure that the fluid will have when it leaves the conduit. This will be measured in bars.