- GCC countries use different cost allocation assumptions, since some considered water as a secondary product of dual purpose plants, while others considered it as a primary product. Desalination plants capital and operation cost decrease significantly as plants capacities increase up to about 5 MCM of brackish groundwater and 8.3 MCM for seawater. Table 8 summaries the capital cost of desalinated water in selected GCC countries. In light of the above, the average cost from GCC countries using different desalination process may range $0.75–1.5 for seawater from large plants and $0.4–1.65 from brackish groundwater per cubic meter. Table 9 shows the comparison of desalination cost with groundwater and wastewater treatment. In general, water production costs in GCC countries where desalination is used extensively are distributed as follows: 38% for capital investment, 20.5% for energy consumption, 21.3% for labor, 16.2% for maintenance, and4% for chemicals [10].