There are 3 time zones in which the cost of the electricity is different. The time where the electricity is the most expensive is called as the peak demand time. In the Minimum waterflow during Peak Demand application, the water pumps are used to fill the water reservoirs during the time where the electricity is cheapest, and the pumps are only operated when there is really need during the peak demand time.  

The energy saving depends on factors such as the capacity of the water reservoir, the supply capacity of the pumps, the conductivity of the pipes, water demand, seasons etc.