In resent years, the performance of sanitary fixtures has changed to more convenient and more comfortable by the progress of technology and the view point of energy saving. Under these conditions, it is supposed that the characteristic of fixture usage has changed in comparison with before. We have advanced the development of calculating method for cold and hot water supply demands based on the fixture usage in the time series through a day. This method is adaptable to office buildings by setting up the calculating model. Therefore, we carried out the investigation about office worker's presence. Also, we measured cold and hot water consumption and temperature in toilets, hot water service rooms and restaurants, and what's more, measured frequency of sanitary fixtures usage in toilets in three office buildings. These measurements were carried out at four seasons over a year and all data were recorded in every one-minute by using flow meters, pulse recorders and some sensors. In this paper, we analyzed the state of office worker's presence and daily, hourly and instantaneous loads of water consumption in each usage. From the results, we clarified the latest tendency of cold and hot water consumption in toilets, hot water service rooms and restaurants in the office buildings.
