Over the last decade because of an outstanding technological advancement concerning desalination technology particularly in RO systems which gave rise to a significant reduction in the cost of desalinated water and ever-increasing water demand, desalination capacity has sharply escalated. Regardless of capital and operating costs, other factors like subsidies or local incentives might cause a significant variation in produced water costs between different areas and facilities. Most of the present cost calculation tools offer limited details and their usages are restricted to certain conditions. Site-specific costs associated with raw materials like transportation and tariffs, the local difference in energy costs, plant retrofit, or treatment are particular conditions that have contributed to higher produced water delivery costs. Hence, the precise estimation of ultimate water cost is extremely challenging as it is highly volatile. As a result, the presence of a highly translucent and well-established methodology to cost estimation will greatly assist in the selection of a suitable desalination technology for each site taking to account all cost-related crucial and affecting factors. The present paper takes into spotlight economic assessment and a thorough exploration of major influential factors which contributed to the total water cost using various desalination methods. To decrease complexity of precise cost estimation, a mathematical modeling to estimate the ultimate water cost of the RO system was proposed. Moreover, the authors propose several recommendations to demarcate future research pathways and minimize water final costs. The application of integrated systems using renewable energy sources, and advancements in material and process design besides increasing unit capacity are current developments that caused a drastic decrease in both cost and energy consumption. The emergence of cutting-edge desalination technologies can have a marked effect on the calculation of cost differences in the future.