The purpose of this study is to review the history of urban water use in Tokyo focusing on two water sources: surface water and groundwater. First, the following four matters are picked up chronologically: expansion of metropolitan waterworks, enhancement of surface water resources, progress of land subsidence, and groundwater pumping. Second, the change of groundwater use and current conservation policies are clarified for some municipalities. Finally, sustainability of urban water use is discussed.
Originally, the water source of metropolitan waterworks was surface water. With increased water demand, the waterworks developed surface water resources in areas remote from Tokyo. Despite increased water demand, groundwater pumping was restricted because of serious land subsidence. Industrial water shifted the water source from groundwater to surface water with the construction of industrial waterworks. On the other hand, groundwater use as residential water has been partially maintained in the Tama Region, western Tokyo. Municipalities in the Tama Region promote policies to maintain groundwater use and recharge.
For sustainable urban water use, efforts both to avoid a further increase of water demand and to maintain local groundwater resources are necessary. Moreover, in terms of water security at the time of a disaster or water shortage, a sustainable urban water supply system should include both an extensive water supply system and a local system of water supply.
