In the late fifties, the use of water closets was encouraged. However, the additional demand created by extensive use of flushing water would aggravate the fresh water shortage problem.
In 1957, in order to save fresh water, the government installed sea water flushing systems in the aided high density development areas of Kowloon. The scheme was proved to be successful, and the system was extended to urban areas and the new towns.
Seawater has a lower standard than fresh water, but it still needs to be treated. The seawater is firstly screened by strainers to remove sizeable particles. It is then disinfected with chlorine or hypochlorite before being pumped to service reservoirs and for distribution to consumers.
Nowadays, some 80% of the Hong Kong population is using sea water for flushing, and the coverage will be increased to 85% in the near future. Hong Kong has taken a pioneering and leading role in the use of sea water as a source of flushing. We have set a good example for coastal cities without adequate fresh water supplies.
Source: Water Supplies Department
Image: Wikimedia Commons