Following the successful implementation of the ‘MAC21’ Project, the ‘New MAC21’ Project is being implemented for further development of membrane technology in Japan. The project includes various pilot-scale and laboratory experiments on 1) nanofiltration system, and 2) MF/UF system combined with advanced treatment processes such as activated carbon treatment, ozonation and biological treatment. As the result, it has been shown that both systems are applicable to drinking water treatment. Although a NF system was very effective for the removal of organic contaminants such as precursors of disinfection by-products, it is considered that the development of a proper treatment method for the concentrate will be very important in the future.