Pui O beach usually receives a ‘Fair’ annual ranking in beach water quality, however high bacterial level can still be occasionally observed during wet season. There are several villages at the hinterland of the beach, most of them store municipal wastewater in septic tanks or soakaway pits. Overflow of bacterial-laden flow from the storage facilities may happen during heavy downpours, leading to deterioration of beach water quality. Therefore, beach salinity is the major water quality indicator at Pui O beach.

Monthly distribution of beach gradings at Pui O beach (2010-2014)