California Water Service

Company Information Contact Information Customer Support Services (Corporate headquarters) 1720 North First Street San Jose, CA 95112 (408) 367-8200 To contact your local Cal Water office or report a problem with your water, visit the Contact Us page. For corporate, investor, and employment information, visit the California Water Service Group web site. California Water Service (Cal Water) is the largest regulated American water utility west of the Mississippi River and the third largest in the country. Formed in 1926, the San Jose-based company serves 480,300 customer connections through 28 Customer and Operations Centers throughout the state. Cal Water is the largest subsidiary of the California Water Service Group, which also includes Washington Water Service Company, New Mexico Water Service Company, Hawaii Water Service Company, HWS Utility Services, and CWS Utility Services. As a whole, the Group provides high-quality regulated and non-regulated utility services to approximately 2 million people in 100 communities. Company-wide, our employees share a commitment to being the leading provider of water and wastewater services and delivering quality, service, and value to our customers.