Abstract: A water lifting system, in particular a fire extinguishing system for offshore installations, such as oil and/or gas production platforms or ships or the like, and a method for operating a water lifting system, is provided. The system includes a pump, a pump-turbine assembly having a pump unit and a turbine unit, and a line connecting the pump-turbine assembly's pump unit output opening and the pump suction opening through which a volume flow (QS) is conducted. The volume flow (QS) include a first partial volume flow (QF) and a second partial volume flow (QT). The first partial volume flow (QF) is conducted to at least one water extraction point and the second partial volume flow (QT) is conducted to the input opening of the pump-turbine assembly's turbine unit.