In order to generate adequate electricity energy, conventional power plants utilize dramatic volume of water resources. Different methods such as replacing cutting-edge technologies of facilities have been proposed to diminish water consumption in this industry. Most of the approaches are considered as medium or long-term solution which requires substantial investment costs. Meanwhile, because of the process and technology, natural gas-fired power plants need less water among conventional power plants. Therefore, shifting unit commitment planning toward these power plants would aid to save water consumption. Nevertheless, overlooking combined cycle power plants can perform negative impact on power plant efficiency, and it may increase power generation cost. This paper aims to investigate multi-objective optimization problem to minimize water consumption by maximizing the power generation efficiency. Hence, this method contemplates economic dispatch by selecting more efficient and less water required power plants. The proposed model is examined on an IEEE 24-bus test system to address the results, and it is compared with the conventional economic dispatch problem to clarify the impact of the proposed approach. According to the results, some relevant conclusions are drawn.