I would like to ask about the installation of rainwater infiltration masu in residential land.

In Yokohama City, we promote the installation of rainwater infiltration masu in the house to recharge groundwater, preserve waterside and greenery, and pass on a good water environment to the next generation.
When we install rainwater infiltration masu in house meeting rainwater infiltration facility setting standard in treatment area, we issue subsidy. (A subsidy will also be issued for replacement from "rainwater masu" to "rainwater infiltration masu" in existing houses.)
When installing rainwater drainage equipment for new construction or renovation of a building, consider setting up a rainwater infiltration masu in the house, and submit a "Inside Rainwater infiltration masu installation examination confirmation letter" when applying for drainage equipment plan confirmation.
In addition, there is land in the city that is not suitable for setting of rainwater infiltration masu. If you want to install it in your home, please contact Environmental Planning Bureau Sewer Management Division or Public Works Office each ward for details.

※Please refer to the following URL.
　・Rainwater infiltration
　・Rainwater penetration masu installation subsidy system in residential land
　・Public Works Office, each district

Rainwater infiltration
Guidance of rainwater infiltration masu installation subsidy system in house
List of Public Works Office