The global industrial sector is under increasing pressure to reduce its water footprint due to escalating water stress and the demands of the circular economy, as well as the Sustainable Development Goals (SDGs). This chapter explores the fundamental principles and sectoral integration strategies necessary for significantly and sustainably optimizing water consumption in industries such as textiles and food processing. It begins by establishing the foundations of water efficiency, discussing tools like water audits, flow mapping, and life cycle assessment (LCA) that help identify bottlenecks and opportunities for reduction. The chapter then delves into technological and systemic integration strategies, focusing on water recycling and reuse systems within manufacturing facilities. Special attention is given to Industrial Ecology and Intersectoral Symbiosis, which aim to transcend the boundaries of individual factories by transforming treated effluents from one industry into resources for another, thereby enhancing water management at the level of industrial parks or watersheds. Finally, the chapter presents decision-making frameworks and case studies to assess the economic, technical, and regulatory viability of optimization systems. The conclusion emphasizes that achieving true efficiency requires close collaboration among industrial stakeholders, regulators, and resource managers, positioning water as a critical element for the competitiveness and resilience of the industrial sector.