The announcement of a water cutback that California could face next year would impact supplies to 25 million of the state's 36.5 million residents and 750,000 acres of farmland, the Department of Water Resources said Thursday.

A wetter winter with more snow in the Sierras could lead California water regulators to increase supplies. In 1993, the state anticipated withholding a record 90 percent of deliveries but didn't have to restrict any after conditions improved. California began delivering water through the State Water Project in 1957.

The restrictions are the result of an ongoing drought and court-ordered restrictions in the state's main water delivery network to protect the endangered smelt fish. The state made the announcement earlier than usual this year to give local water districts and farmers a chance to prepare for the cuts.

The largest water district affected by the announcement is the Metropolitan Water District of Southern California, which provides drinking water to almost 18 million people in parts of Los Angeles, Orange, San Diego, Riverside, San Bernardino and Ventura counties.

"We are preparing for the very real possibility of water shortages and rationing throughout the region in 2009," Jeff Kightlinger, general manager of the Metropolitan Water District, said in a statement.

The Los Angeles Department of Water and Power, San Francisco Public Utilities Commission and East Bay Municipal Utility District mostly get its water from other sources, said Ted Thomas, a spokesman for the Department of Water Resources in the state capital, Sacramento.

Kightlinger expects to experience an extended period of water shortages. "This is not a short-term problem that will be washed away with a few good storms," he said.