Water quality at Ma Wan Tung Wan is quite unstable when compared to most of the other beaches in Hong Kong. Due to its vicinity to the Stonecutter Islands Sewage Treatment Works, water quality at Ma Wan Tung Wan is primarily tidal current driven. With the implementation of the Harbour Area Treatment Scheme stage 2A by the end of 2009, the beach water quality is expected to improve. Although there are no major local pollution sources near the beach, its water quality is found to be significantly correlated with rainfall; in other words, water quality will be further worsen when there is a rain. Both tide level and rainfall are very good indicators of water quality at Ma Wan Tung Wan beach.

Monthly distribution of beach gradings at Ma Wan Tung Wan beach (2010-2014)

Aerial photo and local pollution sources