Evaluation of Rainwater Utilization for Miscellaneous Water Demands in Different Types of Buildings Using Geographic Information System

  • Kim, Jinyoung (Information Analysis & Assessment Center, National Disaster Management Institute, Ministry of Public Administration and Security) ;
  • An, Kyoungjin (Department of Urban Engineering, The University of Tokyo) ;
  • Furumai, Hiroaki (Research Center for Water Environment Technology, The University of Tokyo)
  • Received : 2012.07.25
  • Accepted : 2013.04.24
  • Published : 2013.06.28


This study is an attempt to quantify rainwater utilization and miscellaneous water demand in Tokyo's 23 special wards, the core of the urban area in Tokyo, Japan, in order to elucidate the potential of further rainwater utilization. The rainwater utilization for miscellaneous appropriate water demands, including toilet flushing, air conditioning, and garden irrigation, were calculated for six different types of building: residential house, office, department store, supermarket, restaurant, and accommodation. Miscellaneous water demands in these different types of building were expressed in terms of equivalent rainfall of 767, 1,133, 3,318, 1,887, 16,574, and 2,227 (mm/yr), respectively, compared with 1,528 mm of Tokyo's average annual precipitation. Building types, numbers and its height were considered in this study area using geographic information system data to quantify miscellaneous water demands and the amount of rainwater utilization in each ward. Area precipitation-demand ratio was used to measure rainwater utilization potential for miscellaneous water demands. Office and commercial areas, such as Chiyoda ward, showed rainwater utilization potentials of <0.3, which was relatively low compared to those wards where many residential houses are located. This is attributed to the relatively high miscellaneous water demand. In light of rainwater utilization based on building level, the introduction of rainwater storage mechanisms with a storage depth of 50 mm for six different types of buildings was considered, and calculated as rainfall of 573, 679, 819, 766, 930, and 787 (mm), respectively. Total rainwater utilization using such storage facilities in each building from 23 wards resulted in the retention of 102,760,000 $m^3$ of water for use in miscellaneous applications annually, and this volume corresponded to 26.3% of annual miscellaneous water demand.


Miscellaneous water demand;Rainwater storage;Rainwater utilization potential;Type of building


  1. Water Resources Department, Ministry of Land, Infrastructure, Transport and Tourism. A platform for rainwater and reclaimed water use [Internet]. Tokyo: Ministry of Land, Infrastructure, Transport and Tourism; c2013 [cited 2013 May 1]. Available from:
  2. Wanami K, Shimazu T. Study on rain water use and outflow control (1). In: Annual report of the Tokyo Metropolitan Research Institute for Environmental Protection. Tokyo: Tokyo Metropolitan Research Institute for Environmental Protection; 2004. p.110-116.
  3. Furumai H. Towards the wise management along with urban rainwater. J. Water Waste 2010;52:285-287.
  4. United Nations Educational, Scientific and Cultural Organization; United Nations World Water Assessment Programme. Water: a shared responsibility. Paris: United Nations Educational, Scientific and Cultural Organization; 2006.
  5. Zhou YC, Shao WY, Zhang TQ. Analysis of a rainwater harvesting system for domestic water supply in Zhoushan, China. J. Zhejiang Univ. Sci. Appl. Phys. Eng. 2010;11:342-348.
  6. Watanabe H, Murakami M, Komura T, Moroizumi T, Furumai H. Evaluation of water balance and water use stress in principal cities in Japan. J. Water Waste 2009;51:137-148.
  7. Murakami M, Furumai H. Water quality in urban rainfall and runoff and new trends for their use. J. Water Waste 2010;52:288-296.
  8. Society of Heating, Air-Conditioning and Sanitary Engineers of Japan. Design and operation of a rainwater use system. Tokyo: Society of Heating, Air-Conditioning and Sanitary Engineers of Japan; 1997.
  9. Bureau of General Affairs, Tokyo Metropolitan Government. Report on Establishment and Enterprise Census results for Tokyo [Internet]. Tokyo: Bureau of General Affairs, Tokyo Metropolitan Government; c2011 [cited 2013 May 1]. Available from:
  10. Hijioka Y, Furumai H. Modified washoff models of roof and road for urban non-point pollution analysis. Proc. Japan Soc. Civ. Eng. 2001;(685):123-134.
  11. Ministry of Environment of Japan. Wise adaptation to climate change: report by the Committee on Climate Change Impacts and Adaptation Research. Tokyo: Ministry of Environment; 2008.