The testing of the two different membrane configurations was recently performed at the City of Sarasota's Reverse Osmosis Water Treatment Plant located in Sarasota, Florida. The City owns and operates a 12 mgd water treatment facility, which is comprised of an ion-exchange component and reverse osmosis system. Two pilot-scale testing facilities were designed, constructed and installed onto an existing membrane process train in the Sarasota reverse osmosis water treatment plant process room. Pressure reducing valves were used to control pressure to the pilot test skids. The hollow-fiber membranes were provided by DuPont(R) using their new Double Cartridge (TM) configuration. The spiral-wound test skid was designed as a two-stage system per the requirements of the Safe Drinking Water Act Information Collection Rule. Both hollow-fiber and spiral-wound membrane technologies produced high-quality treated waters relative to sulfate and total dissolved solids. Both technologies were capable of achieving 75% water recovery, however, pressure requirements for the hollow-fiber configuration was approximately double that of the spiral wound technologies. Power cost at 70% recovery was estimated at $0.34/kgal for hollow-fiber technology as compared to $0.13/kgal for spiral-wound technology. Includes 3 references, tables, figures.