The availability of clean water and effective sanitation systems is fundamental to public health, environmental sustainability, and socio-economic development. Engineering Water and Sanitation involves the application of hydrological, environmental, and infrastructure engineering principles to design, optimize, and implement efficient systems for water supply and sanitation. This includes treatment and distribution of potable water, wastewater collection and treatment, stormwater management, and integrating innovative technologies for sustainable resource utilization. With advancements in materials science, computational fluid dynamics (CFD), and automation, the efficiency of water treatment plants, pipeline networks, and decentralized sanitation solutions has drastically improved. The integration of smart monitoring systems and data-driven decision-making has elevated water quality management and system resilience. This article explores key engineering methodologies, cutting-edge technologies, and design considerations for developing robust and sustainable water and sanitation infrastructure.