Water Quality

Over the years, our marine, river and beach water monitoring programmes have helped to provide useful water quality information to the public, monitor long-term changes in water quality, assess compliance with the Water Quality Objectives, provide background data for environmental impact assessment, identify water bodies in need of improvement, evaluate the effectiveness of pollution abatement plans as well as provide scientific data for making planning decisions.

There are noticeable improvements in water quality in Hong Kong over the years. The monitoring has recorded that water quality of rivers across Hong Kong has improved substantially, after a series of remedial measures introduced in the late 1980s and 1990s. In terms of compliance with the statutory WQOs, there was a steady rise in compliance rates. From a less than 50% overall compliance rate in 1986 and 1987, the rate moved steadily upwards through the 1990s to finally beyond 80% in 2000. Since then it has remained more or less steady, with compliance rates around 90% since 2009. The significant improvement displayed by the high compliance rates in recent years were the result of implementation of pollution control legislation as well as the extension of sewer network.

Clear signs of improvement in the water quality of the Victoria Harbour and Tolo Harbour have also been recorded. Despite continuous population growth, excellent water quality has been maintained in Port Shelter and Mirs Bay. In terms of overall compliance with the key WQOs across Hong Kong waters, it has improved from 76% in 1986 to around 80% and above since 2000. The overall compliance rate is based on the combined individual compliance rates of all monitoring stations for the four important key parameters, namely dissolved oxygen, total inorganic nitrogen, unionised ammonia, and where applicable, E. coli.

Similarly, over the years, many beaches have been transformed into popular, safe, and enjoyable places for swimming. The WQO-compliance rate for bathing beaches began with 74% in 1986, dipped to a lowest 58% in 1995 and then steadily improved to 100% since 2010. All gazetted beaches have benefited from the long-term trend of water quality improvement. Beaches with the best quality are mainly located in Southern District on Hong Kong Island, Sai Kung and the outlying islands.

The level of toxic substances in marine water, sediment and marine organisms have generally met overseas standards for the protection of marine life and human health.

Links for the details of the quality of our waters: