Water department officials warned 2 million customers in San Francisco and nearby areas that they still are not conserving enough water to get the region through the winter. "We are not getting the kind of savings to meet the goals this year," said Matt Mullan, a department administrator. He said customers of the Hetch Hetchy water system were asked to reduce consumption by 25% but have actually reduced use by only 10% compared to last year. Hetch Hetchy system managers said water in reservoir storage has dropped to 37% of capacity. Officials warn that storage in the system will hit an all-time low in December if the present rate of consumption continues. The Hetch Hetchy system on the Tuolumne River in Yosemite National Park supplies 90% of the water for San Francisco and San Mateo counties and a major portion of the supply for several South Bay cities.