Numerous countries start suffering from droughts in the last decades due to climate changes and the increment in population, accordingly many governments tend to co-optimize their water and electric networks. Since water-energy nexus (WEN) refers to the usage of water to generate electrical energy and the utilization of this energy to clean, move, store, and dispose of water. Hence, the term WEN flourishes to mitigate the shortage of available drinkable water. Provision for potable water is a must, so the desalination of seawater is the quixotic path to settle this dilemma due to the abundance of saltwater. This work focuses mainly on the desalination of water, choosing Reverse Osmosis (RO) for desalination supports the WEN idea. However, the RO units represent an extra load on the electrical network, which should be managed properly. This paper proposes a new approach to minimize the cost of producing water concerning the electric grid operational costs. With this procedure, the desired demand can be acquired, and the consumption of heavy network components (reservoir, water pump) can be restrained. Hence, provide system sustainability.