The problems associated with the production of drinking water from surface water sources are well known: the increased demand coupled with requirements for better quality (due as well to legislative constraints as to customer demands) has lead to a re-engineering of the water treatment process. Membrane technology, already well established in desalination, is slowly gaining acceptance as one of the possible options for advanced treatment. Four membrane properties are important for the operator of a water treatment plant: high rejection of dissolved organics, low salt rejection, low energy consumption, and stable performance after repetitive cleaning. For a potable water treatment plant, in order to be economically and operationally successful those four criteria have to be met. Although several Filmtec membranes meet most of the above requirements, none was capable of meeting all four at the same time. As reported previously a nanofiltration membrane, now called Filmtec NF200B, was developed for this particular application. This paper demonstrates the difference between Filmtec NF200B and the other nanofiltration membranes manufactured by FilmTec.