The Los Vaqueros Reservoir and watershed is located in the northern Diablo Range, within northeastern Contra Costa County, northern California. It was completed by the Contra Costa Water District (CCWD) in 1998 to improve the quality of drinking water for its 550,000 customers in Central and Eastern Contra Costa County. The reservoir is accessible via Vasco Road, a road which connects Brentwood and Livermore. Some 20,000 acres of land was acquired to provide for construction of the dam and its 1500-acre reservoir, as well as protection of 19,300 acres of associated watershed.