Water is a precious resource. Its demand is rising rapidly and has already exceeded the supply capacity of natural sources in many cities. Airports are spread over vast areas which are normally free from birds and pollution and thus offer immense opportunities for rainwater harvesting which could, to a large extent, meet their non-potable water requirements. This article reviews rainwater treatment procedures at various airports which not only provide a valuable resource for their own consumption but also prevent the entry of pollutants directly into the environment. It also discusses the models and approaches to assess the rainwater harvesting potential of airports on parameters of cost and reliability. It explains the stages involved in the rainwater harvesting systems and how some airports have implemented rainwater treatment systems. Finally, it identifies the gaps at various stages and discusses possible improvements in the near future.