Despite a splash of weekend rain, San Francisco Bay Area reservoirs remain mostly at drought level, officials said. Water officials have called March almost the last hope for a summer without more stringent water restrictions. As has happened repeatedly this year, just when it appeared there could be a break in the drought, rain clouds scudded off and left behind only 0.14 of an inch of rain in Oakland and 0.74 in San Francisco. The Hetch Hetchy Reservoir, heart of San Francisco’s water system, stood at 119,000 acre-feet, about one-third of capacity. The 10 reservoirs of the Santa Clara Valley Water District held only 12,800 acre-feet of water, or only 7.5% of capacity, officials said.