This present disclosure presents a method for metering the amount of tap water usage, while a tap water metering device including multiple measuring sensors is supplied with power through a constant power source, including a step of the tap water metering device receiving tap water from a distribution pipe, a step of the tap water metering device metering the amount of tap water delivered to each of multiple households through a meter in the process of delivering the received tap water to multiple households, and a step of the tap water metering device transmitting the data of multiple meter readings obtained from the multiple meters to the analysis server via telecommunication.