The relationships between the conditions that describe the shape of the flow and power consumption characteristics and the pump design and performance parameters are described. These relations concern: - flow characteristics (throttling curves) described with a fourth-order polynomial, - non-overloading power consumption characteristics of the pump. The pumps that have to exhibit such characteristics are these designed to operate in an arbitrary installation. These pumps must also be characterised by cavitation-free operation in the whole range of discharge variability. In the relations presented, the condition of cavitation-free operation is considered as well.