In recent years, Additive Manufacturing (AM) has transformed the development of new products, enabling more efficient, sustainable, and creative solutions across multiple sectors. Accordingly, this research explores the integration of Selective Laser Melting (SLM) with advanced Computer-Aided (CAx) tools, specifically Generative Design (GD) and Topology Optimisation (TO), to rethink an everyday product. The developed concept, an SLM water tap, highlights the seamless synergy between design and product engineering. Reverse Engineering (RE) was applied to analyse the conventional internal mechanism, which was redesigned in accordance with Design for Additive Manufacturing (DfAM) principles. This approach enabled the integration of the internal cartridge architecture into the tap body as a single metal component, reducing system complexity and part count. TO was applied to key components, achieving a 35% mass reduction without compromising the simulated structural performance of the system. GD was employed to generate optimised internal flow channels, resulting in a numerically simulated flow rate of 4.69 L/min. Integrating CAx tools enabled a customisable product with varied surface textures. This work contributes to the deconstruction of traditional manufacturing paradigms and advances the understanding of AM for functionally relevant product design.