The flux and water quality characteristics of four different types of nanofiltration (NF) membranes were evaluated during this membrane variability study: the NF-90, the NF-70, the NTR7450, and the CAB5 (taken from both an element and a flat-sheet). During each membrane type evaluation, four different flat-sheet samples, cut form the same envelope within a spiral wound membrane element, were tested using the rapid bench-scale membrane test (RBSMT). The specific flux, permeate conductivity and conductivity rejection were measured after 1 hour of operation, and then periodically until the membrane's performance stabilized. The effect of three months of cold storage on the performance of the NF-90 and CAB5 membranes was also evaluated. Includes 11 references, tables, figures.