How safe is Hong Kong’s water?
Direct water usage in the city has increased by 17 per cent per person in the past two decades, prompting safety and environmental concerns
Hong Kong began importing fresh water from Dongjiang (East River) in Guangdong, mainland China, during the 1960s after experiencing water shortages.
About 70 to 80 per cent of our fresh water come directly from Dongjiang, and 20 to 30 per cent come from local catchments, according to the government. The water supply agreement with mainland China is subject to continuing reviews. Pressure on the Chinese government to reduce the nation’s water consumption may result in increasing limits on Hong Kong’s supply in the future.
Treatment process There are 21 water treatment works in Hong Kong. The city’s water undergoes a “series of rigorous processes” in order to meet the standards for drinking water set by the World Health Organisation, a spokesman for the Water Supplies Department said.
“Water is dosed with chemicals and mixed for coagulation and flocculation. It then passes to the clarifiers where the settlement of impurities in the water will take place,” he said. “Clarified water then flows into filters for sand and anthracite, to remove the more finely divided particles.
“The filtered water passes into contact tanks where chlorine and hydrated lime are added respectively to disinfect and control the pH of the treated water. Fluoride is also added for dental protection.
“A small amount of residual chlorine is maintained in the water to prevent bacterial growth on the rest of its journey. The treated water is pumped into a system of water mains, stored in service reservoirs and then supplied to the public.”