Banjar society heavily depends on river water. However, the current water quality have been unsuitable, even can be classified dangerous. Water pollution of rivers in South Kalimantan was caused by the activities of its own citizens, such as industrial processes, mining, and excreta disposal by people around the river. Onfortunately, in Martapura River found heavy metal pollution which are beyond the threshold. East Martapura District part of the population in many regions of Martapura River behaves using river water for everyday purposes such as activity MCK (Bath-Wash-lavatory).The purpose of this study was to determine the pattern of behavior of riverside communities in activities Martapura MCK (Bath-Wash-lavatory) in East Martapura District. The method of this research is qualitative research with 3 informants who lived in riverside Martapura. The results shows the motives that why people still doing MCK activity are because heredity factor, easy to interact with people on their neighbourhood, more practical, easy, and does not required any cosy while using water, and feel more cleaner to wash. This motives that makes a riverside society have their MCK activities keep alive in Martapura riverside. Keywords: motive, river, bath, wash, lavatory