Providing an adequate water supply for Hong Kong has always been difficult because there are no natural lakes, rivers or substantial underground water sources. The annual rainfall averages 2 431.2 millimetres but this is insufficient to meet current demands - the average daily consumption of potable water during 2021/22 being 2.89 million cubic metres.
The Water Supplies Department is a government department providing potable water to the people living within the Hong Kong Special Administrative Region. The department also supplies sea water for flushing.
Hong Kong's two main sources of water are rainfall from natural catchments and Dongjiang water from Guangdong Province. Shortage of natural storage reservoir sites led to the construction of Hong Kong's first ‘reservoir in the sea' at Plover Cove. The initial scheme, completed in 1967, was created by damming, and draining an inlet of Tolo Harbour and had a storage capacity of 170 million cubic metres. The storage capacity was increased in 1973 to 230 million cubic metres by raising the dam. A similar but larger scheme at High Island, completed in 1978, has a capacity of 281 million cubic metres. The total storage capacity of Hong Kong's reservoirs is 586 million cubic metres.
Dongjiang is Hong Kong's major source of water. Dongjiang water first started to be supplied to Hong Kong in 1965. Today, about 70-80 per cent of water comes from Dongjiang by arrangement with the Guangdong authorities. 784 million cubic metres of Dongjiang water was imported in 2021/22. The Dongshen-Hong Kong water supply system is designed to be capable of providing Hong Kong with 1.1 billion cubic metres per annum.
An interesting facet of the waterworks is the sea water supply systems with their separate networks of distribution mains, pumping stations and service reservoirs. In 2021/22, an average of about 876 000 cubic metres of sea water was supplied each day.
| Fresh Water | 2020/21 | 2021/22 |
|---|---|---|
| Annual Consumption | 1 033.81 | 1 056.23 |
| Daily Average Consumption | 2.83 | 2.89 |
| Highest Daily Consumption | 3.05 | 3.10 |
| Sea Water | 2020/21 | 2021/22 |
|---|---|---|
| Annual Consumption | 317.93 | 319.79 |
| Daily Average Consumption | 0.87 | 0.88 |
About one-third of Hong Kong's 1 110 square kilometres has been developed as water catchments.
| 2020/21 | 2021/22 | |
|---|---|---|
| Rainfall (in mm) | ||
| Rainfall recorded by the Hong Kong Observatory | 2 324.7 | 2 506.8 |
| Average rainfall recorded in water catchments | 1 966.3 | 2 200.9 |
| Yield (in million cubic metres) | ||
| Old Reservoirs | 88.17 | 88.97 |
| Plover Cove and High Island Systems | 124.41 | 134.41 |
The impounding reservoirs and their storage capacities are tabulated below:
| Name of Impounding Reservoir | Year on Supply | Storage Capacity (m3) |
|---|---|---|
| Pok Fu Lam Reservoir | 1877 | 233 000 |
| Tai Tam Upper Reservoir | 1889 | 1 490 000 |
| Tai Tam Byewash Reservoir | 1904 | 80 000 |
| Tai Tam Intermediate Reservoir | 1907 | 686 000 |
| Kowloon Reservoir | 1910 | 1 578 000 |
| Tai Tam Tuk Reservoir | 1917 | 6 047 000 |
| Shek Lei Pui Reservoir | 1925 | 374 000 |
| Kowloon Reception Reservoir | 1926 | 121 000 |
| Aberdeen Lower Reservoir | 1931 | 486 000 |
| Aberdeen Upper Reservoir | 1931 | 773 000 |
| Kowloon Byewash Reservoir | 1931 | 800 000 |
| Shing Mun Reservoir | 1936 | 13 279 000 |
| Tai Lam Chung Reservoir | 1957 | 20 490 000 |
| Shek Pik Reservoir | 1963 | 24 461 000 |
| Lower Shing Mun Reservoir | 1965 | 4 299 000 |
| Plover Cove Reservoir | 1968 | 229 729 000 |
| High Island Reservoir | 1978 | 281 124 000 |
Hong Kong is dependent on adequate storage for the maintenance of a regular supply. If you want to know the storage position of impounding reservoirs, please visit "Current Storage Position of Impounding Reservoirs"
| 2020/21 | 2021/22 | |
|---|---|---|
| Additional no. of accounts (nett) | 38 100 | 43 100 |
| No. of accounts as at April 1 | 3 115 900 | 3 159 000 |
The drinking water supply is fully treated in the sequence of chemical coagulation, clarification (at most treatment works), filtration, ozone/chlorine disinfection, pH value adjustment and fluoridation. The drinking water is soft in character and conforms wholly to the Hong Kong Drinking Water Standards.