Although water covers around 71% of the earth’s surface, 98% of that water is unusable due to its salinity and cannot be utilised as drinking water. Two of the most important problems facing humanity in the twenty-first century are the scarcity of water and the quality of drinking water. There are several reasons why water can become contaminated, but chemical pollution poses a serious worldwide risk due to its extreme toxicity. A life cycle assessment (LCA) is a standardised method to quantitatively assess such environmental impacts. This study goes beyond LCA of wastewater treatment technologies for the sustainable evolution of enterprises in order to address these concerns. Hotspots are those points in the life cycle that have substantial negative influence on the environment. Possible hotspots can be determined using it, trade-offs can be comprehended, and more environmentally friendly wastewater treatment technologies can be created. Most often, resolving hotspots becomes the cornerstone of the sustainability plan based on a complete LCA. Existence Cycle Assessment (LCA) is a thorough methodology that evaluates how different products, activities, or systems affect the environment over their whole life. Conceptual, simplified and detailed LCA is utmost important to evaluate the sustainability of wastewater treatment systems. This chapter walks the reader through the LCA technique step-by-step so they may decide on the scope and aim with knowledge. It also includes variables to include and their sources for inventory acquisition, as well as the selection of the functional unit and system boundaries. Viewpoints on impact assessment method selection and effective strategy selection are also covered.