Utility water system with a pressureless storage container, particularly for solar installations

A warm water storage system for supplying warm water under pressure to a network including a warm water storage tank where the pressure above the water level in the tank is equal to ambient pressure, a pressurized cold water supply connecting with a cold water region of the tank, and a warm water takeoff region of the tank connecting with said network, characterized in having a warm water booster pump positioned between said warm water takeoff region and said network, and in having a positive displacement cold water motor connected to said booster pump and positioned between the cold water supply and the cold water region such that the pressure of said cold water supply will drive the motor to in turn drive the booster pump such that pressure in the cold water supply is transferred to said network.