The invention is a new system for mixing water and regulating the flow rate, comprising an electric control and supply unit (Zi) and a manifold-mixer (C) comprising in turn one or more solenoid valves (Ei) connected to and regulated by suitable electronic adjusting devices (P, Pm, Pp), and wherein each solenoid valve (Ei) comprises two through holes (F1) and (F2) for connection to the hot water (Tc) and cold water (Tf) pipes and at least one further hole (F3) for the insertion of a supply pipe (Ti) that conveys water to the sanitary fixture (Ui) to which water must be provided. Said solenoid valves (Ei) may be connected to the same two hot water (Tc) or cold water (Tf) pipes, and be positioned side by side or overlapped. The electric control and supply unit (Zi) processes the data coming from the adjusting knobs (N) and feeds the solenoid valves (Ei). The system also comprises one or more sensors (flood sensor Sa, temperature sensor, pressure sensor, etc) and presence detectors and vocal controls for regulating the flow rate and the mixing ratio of the water being dispensed.