The United States imports vehicles, equipment, fresh produce and other goods from Mexico. That list may soon include water too, now that a San Diego County water district is looking south for help to diversify its supply. The Otay Water District serves a population of 220,000 people in southeastern San Diego County, in a service area spanning 125 square miles, from the border city of Chula Vista to the unincorporated areas in Jamul. It currently buys potable water from the Metropolitan Water District of Southern California, the San Diego County Water Authority and the Helix Water District.