The P18.72 billion New Centennial Water Source-Kaliwa Dam project of the Metropolitan Waterworks and Sewerage System has attracted six bidders, which include conglomerate San Miguel Corp., the Public-Private Partnership Center announced yesterday. San Miguel Holdings Corp. and five other prospective bidders, namely Leighton Contractors, Abeinsa Infraestructuras , Armando U. Khong Hun General Contractor, Datem Inc. and Pan Pacific Renewables Power Phils.