Modern heating systems are a complex set of equipment and elements, the main task of which is to provide comfortable conditions in the serviced premises, regardless of external deflecting factors. Water heating systems with variable hydraulic mode are the most common type of heating in newly constructed residential and public buildings. The installation of differential pressure regulators in individual heating systems is mandatory from the point of view of ensuring noiseless operation and reducing the mutual influence of regulatory areas. However, the location of their installation is controversial in the professional community. This paper covers the range of hydraulic modes of operation of two variants of the design of individual heating system used in this practice of system design: installation of only floor-by-floor collectors, followed by the connection of internal apartment circuits, or with the installation of additional collectors in each apartment. Formulas for estimating changes in the coolant flow rate during operation with high-quality individual control of the system are proposed. The values of the degree of opening of the regulators in the entire permissible range of operation of the system, the hysteresis and the pressure loss created by the differential pressure regulator are obtained. Conclusions are drawn about the rationality of using the proposed designs of the apartment-by-apartment heating system