Please regularly clean the rainwater infiltration facilities!

In Inagi City, we are promoting the development of rainwater storage and infiltration facilities to manage the rain that falls within the city.

This rainwater retention and infiltration facility can be installed on your property.
By installing the rainwater retention and infiltration facility, the amount of rainwater flowing into the city's waterways and rivers will be reduced, helping to prevent flooding.
To protect your home and the community from flooding caused by frequent localized heavy rains, we ask for your cooperation in installation and management.

Facilities for Infiltrating Rainwater

Examples of rainwater infiltration include rainwater infiltration pits and infiltration trenches.
By allowing rainwater to infiltrate underground, it becomes groundwater and can be effectively utilized as a healthy water circulation resource.

Rainwater infiltration pit

Rain that falls on the roof is directed to the rainwater infiltration pit via gutters and other means.
One rainwater infiltration pit with a diameter of 25 centimeters has the capacity to infiltrate approximately one bathtub's worth of rainwater into the ground per hour.

Rainwater infiltration tanks allow rainwater to permeate through the holes in the bottom and sides, as shown in the photo below. Please clean them regularly to ensure that the infiltration function is not compromised by sediment or fallen leaves.

Infiltration Trench

In addition to rainwater infiltration pits, further infiltration effects can be achieved by installing infiltration trenches.
Although it is not visible in daily life, it can be constructed on the premises as shown in the photo below. Rainwater infiltrates through the perforated pipes and the gravel at the bottom.

Rainwater Storage Facility

As an example of rainwater storage, there are storage tanks. By installing a storage tank, rain that falls on roofs and other surfaces can be temporarily stored and used as valuable water for home gardens, trees, and during disasters.
Additionally, during heavy rainfall, it is possible to prevent concentrated drainage by storing the water and delaying the discharge time.

Preparation for Flooding

Maintenance and Management of Rainwater Infiltration and Storage Facilities

By properly maintaining and managing rainwater retention and infiltration facilities, their capacity can continue to be fully utilized.
We kindly ask you to regularly clean the sand and fallen leaves that accumulate in the rainwater infiltration pits and retention tanks.

Additionally, because the rainwater retention and infiltration facilities are buried underground, their location, scale, and maintenance may not be sufficiently confirmed as they are not usually visible.
Please check the rainwater retention and infiltration facilities at your home and ensure regular maintenance.

Rainwater Management Enhancement Month

In Tokyo, June is designated as Rainwater Management Enhancement Month every year, and we ask everyone to prepare for flooding.
If you put garbage or other items into the "rainwater drains" or "ditches" installed within your property or along the roads, rainwater will not flow in, increasing the risk of flooding.
Let's regularly clean around the "rainwater drains" and "ditches" to ensure that rainwater flows smoothly.

• Tokyo Metropolitan Sewerage Bureau(External Link)

Provision of Rainfall Information

The Tokyo Sewerage Bureau provides real-time updates on rainfall information through "Tokyo Amessh" available on the internet.
When heavy rain is expected, let's check the news and information such as "Tokyo Amessh" to prepare.

• Tokyo Amesh(External Link)