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

Yokohama City promotes the installation of rainwater infiltration masu in the house in order to recharge groundwater, preserve the waterside and greenery, and pass on a good water environment to the next generation.
In the treatment area, a subsidy will be issued when installing a rainwater infiltration masu in the house that meets the rainwater infiltration facility setting standards. (A subsidy will also be issued for the replacement of "rainwater masu" to "rainwater penetration masu" in existing houses.)
When installing rainwater drainage facilities for new construction or remodeling of buildings, consider setting of rainwater infiltration masu, and please submit "house rainwater infiltration masu setting examination confirmation" at the time of drainage equipment plan confirmation application.
In addition, there is land which is not suitable for setting of rainwater penetration masu in the city. When installing in the house, please contact Environmental Planning Bureau Sewer Management Division or Public Works Office in each ward for details.

※Please refer to the related website.
　・Rainwater infiltrate
　・Rainwater penetration masu installation subsidy program in residential land
　・Public Works Office in each ward

Rainwater infiltrate
Guidance of rainwater infiltration masu installation subsidy program
List of Public Works Office in each ward