RO is being used for desalting a variety of feedwater, but its use with subsurface water has not been investigated in Kuwait before. The reliability of the RO technique depends upon the extent of pretreatment that must be designed to reduce suspended, biological fouling and colloidal materials in the feedwater. Therefore, the Kuwait Institute for Scientific Research implemented a project to assess the viability and economic feasibility of using RO technology to desalinate subsurface water. This paper discusses 2200 operating hours performance data of the RO plant used to desalinate subsurface water. Results indicates that RO is a viable technique to desalinate this type of water. The improvement in TDS, GOD, BOD and total count values were 99%, 96%, 42% and 47%, respectively.