Under the pressure of water crisis occurring all over the world and, with the latest technology available, the feasibility and benefit of implementing alternative water resource projects is now a reality. The development and implementation of such projects is however a complex and difficult task because of the different disciplines that are involved: water, environment, economy, finance, social, communication, technique and technology, legislation and geography. Based on the water cycle and application cases, this paper explains why the development of alternative water resource includes the use of treated wastewater, desalination, aquifer recharge, hybrid systems, or a combination of them, is to be made in a context of integrated water resource management. It also discusses the complexity of the decision making process and gives some key elements that can facilitate the acceptance of the project.