The sustainability of hydraulic systems, specifically rainwater tanks, centres on key principles such as water conservation, energy efficiency, and reduced environmental impact. Rainwater tanks contribute to sustainability by capturing and storing rainwater, decentralizing water supply, and minimizing reliance on centralized systems. Factors like material durability, proper maintenance, water quality management, and community education further enhance the sustainability of rainwater tank systems. Integrating these considerations promotes responsible water use and supports long-term viability.