Rainwater Infiltration in Private Properties
Rapid urbanization of Tokyo has diminished the ability for storm water to soak into the ground. This interruption in the water cycle is a cause of water damage unique to urban areas.
During heavy rain in areas with a combined sewer system, stormwater mixed with wastewater is discharged into rivers and the sea. The combined sewer system is a cause of water contamination.
To address this issue, the Tokyo Metropolitan Government has partnered with local ward authorities to install water penetration mechanisms which will allow storm water to soak into the ground in private properties.