The paper describes the operational experience with the newly constructed SWRO plant in Jersey. The plant replaced a multi-stage flash distillation (MSF) plant, commissioned in 1970 by Weir Westgarth, which was operational until 1996. At the time of supply the MSF plant was considered to be the most energy efficient desalination process with a gain ratio of 12 to 1 to minimize running costs. Projected operating costs for the new SWRO plant are compared with the actual running costs as well as with actual running costs for the original MSF plant. The environmental impact of both installations is also addressed. For this particular site the benefits of membrane technology are clearly demonstrated.