The operation of the first reverse osmosis (RO) plant for brackish water desalination in Croatia is described. The equipment was installed on one of a thousand Croatian islands, the majority of which are lacking a fresh water supply. This paper contains comparison data calculated in a feasibility study and provided by the manufacturer, Universal Aqua Technologies, Inc. (USA) in their specifications for RO Model TP 80 K, with results obtained during the first year of operation of this equipment. The productivity data, the data on the quality of the produced drinking water, and the feed water salinity data are shown graphically. Also presented are the basics of the operation and the maintenance of the equipment during this period.