Hong Kong enjoys one of the safest and most reliable water supplies in the world. The Water Supplies Department (WSD) is responsible for operating and maintaining fresh water and sea water supply and distribution systems to ensure a reliable water supply to the customers. The fresh water supply system covers not only the populated city centres and satellite towns but also rural areas and villages covering a total of 99.99% of Hong Kong’s population. On the other side, the seawater supply network for flushing covers about 85% of the Hong Kong's population.
Fresh water supply mainly involves three key processes, viz collection of raw water, water treatment and distribution. Raw water from the impounding reservoirs and Dongjiang is delivered by large transfer mains and tunnels to water treatment works for treatment. Treated water is then pumped through large trunk mains or tunnels to service reservoirs and then flows by gravity via the distribution network to the various buildings – residential, commercial, hotels and restaurants, factories and warehouses, etc. – and arrives at the destination of its delivery journey – the tap.
The sea water supply system is completely separated from the potable water supply system. The system normally uses a “balance tank” configuration. Sea water is directly pumped to the customers with surplus water delivered to and stored at the service reservoirs.
