This paper proposes a sustainable greywater management system designed to reduce freshwater consumption and mitigate wastewater generation through the reuse of water from domestic sources such as sinks, showers, and laundry. The study presents a low-cost and efficient greywater treatment method combining physical filtration and biological processes to produce water suitable for non-potable uses, including landscape irrigation and toilet flushing. The system was evaluated for performance based on key water quality parameters, and the treated greywater was found to meet applicable environmental and health standards. Through field implementation and analysis, the project demonstrates the potential for substantial water savings, reduced strain on conventional water supply systems, and improved environmental outcomes. The proposed framework is scalable and adaptable for residential and institutional applications, offering a practical solution for water conservation in both urban and rural settings. This work contributes to the development of integrated water resource management strategies in the context of increasing global water stress.