SACRAMENTO — California’s water managers on Tuesday preliminarily allocated just 10% of requested water supplies to agencies that together serve more than 27 million Californians and 750,000 acres of farmland.

The state Department of Water Resources cited the dry start to the winter rainy season in California’s Mediterranean climate, along with low reservoir levels remaining from last year’s relatively dry winter. Winter snow typically supplies about 30% of the state’s water as it melts.

Last year’s initial allocation also was 10% and climbed only to 20% when the final allocation was made in May. Most areas that depend on the state-supplied water also have other sources including groundwater, streams and their own reservoirs.

The department’s eight precipitation measuring stations scattered across Northern California collected a record-low 0% of average rainfall in October and 53% in November.

Meanwhile, the state’s major reservoirs are lower than they were at this time a year ago.

Lake Shasta, the federal Central Valley Project’s largest reservoir, is at 75% of its historical average, down from 119% a year ago. Lake Oroville, the State Water Project’s largest reservoir, is at 61% compared to 90% last year.

“While we still have several months ahead of us, dry conditions persist,” department Director Karla Nemeth said in a statement urging the state’s nearly 40 million residents to conserve water. “As communities throughout California prepare to support their environment and economies through times of extended dry periods, state agencies plan together to support those communities.”

The initial allocation uses conservative assumptions and is updated monthly as conditions change based on snowfall and water runoff. The department will conduct this winter’s first snow survey south of Lake Tahoe on Dec. 30.