Recent years, a variety of infrastructure-mediated sensing methods have been proposed to recognize activities of daily living (ADLs). However, due to the inconvenience such as high-cost, difficult-to-install, intrusive and applicable to the house with specific architectures alone, existing water-use activity recognition methods cannot be widely used into people's houses. In this paper, a single-point infrastructuremediated sensing technique is proposed for water-use activity recognition. A single 3-axis accelerometer sensor is attached to the surface of the main water pipe in the house to detect and collect the vibration signals of the main water pipe. These signal data are then processed through six modules in the proposed activity recognition system. Four classes of water-use activities (Bathing, Flushing toilet, Cooking and Washing) are classified by the system and experimental results show that our system can recognize about 70.37% water-use activities.