<p>Forward osmosis (FO) is an emerging process in the field of water/wastewater treatment. Water treatment using the FO process will address the ongoing problem of water scarcity. The commercial application of the FO system is very limited due to several issues like low water flux, concentration polarization, draw solution availability and regeneration, and membrane fouling. The present study focuses on the FO system’s design methodology for water and wastewater treatment applications. This will focus on the process design (system application), draw solution/feed solution selection, membrane selection, mode of operation, desired recovery and output, and pump and flow rate selection. The function design methodology will accelerate the application of the FO system at the pilot level and commercial level. The study also focuses the mitigating technology’s challenges and problems, like membrane fouling, concentration polarization, lower water flux, and recovery. The study will recommend the design methodology for the large-scale FO for water and wastewater treatment.</p> Graphical Abstract <p></p>