水資源の有効活用


Efficient use of water resources

Water conservation through usage of rainwater and intermediate-grade water

Water is one of our most useful resources. In buildings, it has a wide variety of applications from flushing toilets and watering plants to serving as a thermal medium for air-conditioning systems. Annual usage can reach tens and even hundreds of thousands of tons. Mori Building collects and stores all the rainwater runoff from all the buildings in the ARK Hills development listed below in reservoirs, and then effectively uses this precious water resource after filtering. At Roppongi Hills and other large-scale development projects, we also adopt systems that use wastewater (non-sewage and relatively low contamination) as intermediate-grade water (non-drinkable for general use) such as flushwaster for toilets and other applications, further enhancing our conservation and responsible use of water.

  • Utilization of Intermediate-grade water and rainwater at Roppongi Hills
  • Utilization of Intermediate-grade water and rainwater at Roppongi Hills



  • Roppongi Hills rainwater collection/storage tank location map

In the fifth basement level of Mori Tower, our intermediate-grade water processing facility can process approx. 980 tons per day. Rainwater storage tanks are located at 13 sites in the area and have a total capacity of 6,750m3. This rainwater is mainly used as supplemental water for the cooling towers of our DHC facility after it has been filtered.

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