Water is an indispensable resource; however, its availability and quality are increasingly threatened by pollution and scarcity. Nanotechnology, owing to its unique nanoscale capabilities, offers promising solutions for sustainable water and wastewater management. However, along with its potential benefits, nanotechnology presents challenges that must be addressed for its effective and responsible implementation. This chapter explores the challenges and future perspectives of nanotechnology for sustainable water and wastewater management. Nanotechnology offers potential solutions to pollutant removal, energy consumption, scalability, and environmental safety. Recent advancements in nanomaterials and nanotechnological approaches have provided solutions to these challenges. Nanomaterials, such as TiO2 nanoparticles and graphene oxide, have shown exceptional properties for pollutant removal. Nanotechnology enables the development of energy-efficient water treatment processes and the real-time monitoring of water quality parameters. Scalability and cost-effectiveness are critical factors for the practical implementation of nanotechnology in water treatment. The integration of nanotechnology with conventional treatment methods allows for the development of hybrid systems that capitalize on the strengths of both approaches while mitigating their respective limitations. The challenges faced by nanotechnology include environmental safety concerns regarding the potential release of nanomaterials into the environment, necessitating thorough risk assessments and mitigation strategies. Future research should focus on overcoming scalability barriers, optimizing the energy efficiency, and ensuring the environmental safety of nanomaterials. By harnessing the potential of nanotechnology and interdisciplinary collaborations, sustainable solutions for water and wastewater treatment can be realized, contributing to global efforts toward environmental preservation and resource conservation.