Imported water is a major resource for industry in California, but its ever-increasing costs are leading to alternative methods for meeting water supply needs. This paper discusses how the use of membrane technology for the treatment of wastewater effluent is helping one Southern California agency relieve its dependency on expensive imported water. It describes the treatment process and the performance of a facility that converts the wastewater effluent to high quality water suitable for industrial use. The West Basin Municipal Water District's Phase III Expansion project at their water recycling plant in El Segundo, California treats secondary effluent received from the City of Los Angeles' Hyperion Treatment Plant to provide water to the Chevron refinery. The purpose of the expansion is to provide high quality water suitable for use as boiler feed water in the Chevron refinery. Chevron requires two grades of water. The less stringent grade requires water quality of 0-mg/l calcium, 0-mg/l magnesium, 1.5-mg/l silica, 0.3 mg/l as CaCO3 total hardness, and 60 mg/l total dissolved solids. The higher quality grade provides water with 0-mg/l calcium, 0-mg/l magnesium, 0.1-mg/l silica, 0.03 mg/l as CaCO3 total hardness, and less than 5 mg/l total dissolved solids. To meet these requirements, the project provides microfiltration and reverse osmosis treatment of secondary effluent wastewater received from Hyperion. This paper will provide an overview of the project goals, the processes and the equipment necessary to achieve the goals, as well as the method of delivery of the construction project. Includes 6 references, tables, figures.