Abstract1Hong Kong has suffered from gross water pollution, as a direct consequence of the territory's rapid growth in population and in industrial and commercial prosperity. In 1989, the government of Hong Kong adopted a comprehensive strategy for water pollution control. Water quality monitoring is essential to the success of this strategy.2The monitoring programme was designed rationally to provide the information required to detect progress towards (or away from) water quality objectives. Practical constraints have prevented the ideal implementation but the programme gives comprehensive coverage of marine waters, including bathing beaches and inland waters.3Sampling and analytical methods are an important part of programme design, to ensure that the programme yields accurate and consistent data. Presentation and interpretation also need to be taken into account. More effort on interpretation of a well‐designed survey can reduce the effort required for sampling and analysis.4Examples show how the monitoring programme has been used for practical environmental management purposes, including the control of dredging operations, the justification of new sewage disposal facilities, and the control of waste from the livestock industr