Section 222(1) in West Bengal Municipal Corporation Act, 2006
(1)All public drains, and all drains in, alongside, or under, any public street, whether made at the charge of the Municipal Fund or otherwise, and all works, materials and things, appertaining thereto, which are situated within the Corporation area, shall vest in the Corporation:Provided that the Corporation may, with the approval of the State Government, make over the trunk-sewers, sewage treatment plants, pumping stations and other utilities to a separate and independent agency for maintenance and development, and it shall be lawful for such agency to construct new trunk-sewers, sewage treatment plants, pumping stations, or other utilities.