This study aims to obtain the knowledge necessary for constructing an urban water recycling system in Beijing City. A macro-scale water balance model was constructed for Beijing City according to statistical data, and domestic water demand structure in the city was analyzed through a survey of 124 families living in the Haidian district in 2006. Annual per capita water use in Beijing City was 220 L, and about 75% of it was used for cooking, washing, showering, and toilet flushing. The use of reclaimed wastewater for toilet flushing and room cleaning, which was estimated as 22% of domestic water demand, was deemed acceptable by most of households questioned. Finally, we estimated the effect of supplying reclaimed wastewater for municipal use by macro-scale water balance estimation based on the structure of municipal water demand. Assuming that 60% of treated sewage is reclaimed from 41% of the current total, this would result in a saving of 122 million m3 of the groundwater required. Moreover, with the useful ratio of reclaimed wastewater set to 80% and 100%, 250 million m3 and 377 million m3 of groundwater, respectively, can be saved.
