California Water Service Group is a water utility company that provides service to more than 2 million people located in more than 100 communities. The company is comprised of several subsidiaries, including California Water Service Company, Washington Water Service Company, New Mexico Water Service Company, Hawaii Water Service Company and CWS Utility Services. The largest of these subsidiaries is California Water Service Company, an investor-owned water utility company that was formed in 1926. It serves more than 500,000 customers through more than 35 customer and operations centers throughout the state of California. California Water Service Group is headquartered in San Jose, Calif.