In the past decades, the demand for potable and usable water has been on a continual increase, while its availability has been on an exponential decline. Studies have argued that, by 2050, only a small fraction of the world's population will have access to clean and safe water, thereby exposing a significant portion of the population to a serious water crisis. Large volumes of wastewater are generated yearly, both domestically and industrially, and the necessity to develop effective and efficient strategies and technologies to recover these wastewaters and turn them into safe and reusable waters is a momentous concern among scientists and policymakers. Across the globe, governments are developing approaches and strategies to mitigate both short-and long-term water challenges resulting from various anthropogenic activities that have contributed to the rising degradation of water quality, coupled with the attendant negative impact of natural disasters, increasing urbanization, among others. Notwithstanding, the advancements in nanotechnology have made it possible to engineer novel and innovative polymer-based materials and composites that possess desirable and even predictable properties for targeted applications, which has presented the opportunity for the development of cost-effective nanotechnologies and processes employed in water remediation, reclamation, purification, and treatment processes worldwide. Nevertheless, these innovative technologies and processes have also been shown to have their limitations and challenges in the enhancement of water quality. Herein we survey the current advancement of selected polymer-based membranes and composites and their intervention for the production of safe, potable, and usable water, as well as their limitations, challenges, recommendations, and future perspectives.