In this 21st century, water-related environmental challenges such as pollution, scarcity, and the diminishing availability of freshwater have become increasingly critical. The concept of water footprint (WF) offers a valuable useful tool to address these pressing issues. This book chapter explores the connection between freshwater consumption and key environmental challenges. The WF concept garnered significant attention from stakeholders both within and outside the scientific community. Its applications have proved to be highly versatile, particularly in assessing strategic corporate risks related to water pollution and scarcity. This chapter provides an in-depth discussion on the fundamentals of WF, tracing its origins, purpose, and operational mechanisms. It also highlights the evolvement of water footprint assessment (WFA) over the last two decades. Furthermore, this chapter demonstrates how WFA has become an effective instrument for raising awareness of global water issues among decision-makers in both government and industry sectors. The challenges associated with WF and WFA, particularly in the context of outsourced water pollution, are also critically examined. This chapter serves as a foundational resource for understanding the WF concept, emphasizing the importance of WFA, and exploring the associated challenges.