Industrial wastewater reuse is always a good idea, especially in arid and environmentally sensitive areas where wastewater discharge is restricted. However, when it comes to implementation, the bottom-line is always economics–is it economically feasible and what is the payback? This paper describes a major industrial wastewater reuse project that will not only solve many water-related problems but is economically attractive for a large petrochemical plant. The petrochemical plant daily uses a large amount of fresh water but is located in a water-limited area with recurring seasonal droughts. Water rationing during the droughts has caused operational difficulties and petrochemical production cutbacks. In addition, the total dissolved solids (TDS) concentration of the water supply has been increasing due to salt water intrusion, causing short production cycles for the plant’s ion exchange-based water demineralization (DI) system.