Sustainability of toilet flushing water supply in Hong Kong

Hong Kong is an Asian city with nearly 7 million people. Because of the lock of natural resources, the local water supply is not adequate to meet the demand. Fresh water supply in Hong Kong relies on the cross border import of water from the East River (Dongjiang) in China, To conserve fresh water, seawater has been used for toilet flushing since the 1950s. In this paper, the current status of seawater for toilet flushing in Hong Kong is reviewed, and the future strategy toward sustainable toilet flushing water supply, including other alternatives, is discussed