Less visible but no less important are the water-saving and recycling features enabled by the building's grey water recycling system. Grey water includes wastewater from showers, washbasins and kitchen areas. Grey water is collected, subjected to biological and micro-filtration treatment, disinfected, adjusted in acidity and then stored in underground tanks for re-use for toilet flushing. The average design flow of the system is 26,000 litres per day, adequate to serve a maximum of 2,500 persons, which comfortably caters for the needs of headquarters' onsite staff.

The new EMSD headquarters building is a showcase of the latest energy saving technologies and renewable energy applications. It is a particularly fitting location for EMSD's professional engineers and managers who work to push back the frontiers of applied technology and pioneer new public services for the benefit of Hong Kong.