SACRAMENTO, Calif. — Amid an epic drought, California officials announced Friday they won’t send any water from the state’s vast reservoir system to local agencies beginning this spring, an unprecedented move that worsens a precarious situation for 25 million people and 1 million acres of farmland.

The announcement marks the first time in the 54-year history of the State Water Project that such an action has been taken, but it does not mean that every farm field will turn to dust and every city tap will run dry.

The 29 agencies that draw from the state’s water-delivery system have other sources, although those also have been hard-hit by the drought.

Many farmers in California’s Central Valley, one of the most productive agricultural regions in the country, also draw water from a separate system of federally run reservoirs and canals, but that system also will deliver just a fraction of its normal water allotment this year.

The announcement affects water deliveries planned to begin this spring, and the allotment could increase if weather patterns change and send more storms into the state.

Nevertheless, Friday’s announcement puts an exclamation point on California’s water shortage, which has been building during three years of below-normal rain and snow.

“This is the most serious drought we’ve faced in modern times,” said Felicia Marcus, chairwoman of the State Water Resources Control Board. “We need to conserve what little we have to use later in the year, or even in future years.”

State Department of Water Resources Director Mark Cowin said there simply is not enough water in the system to meet the needs of farmers, cities and the conservation efforts that are intended to save dwindling populations of salmon and other fish throughout Northern California.

For perspective, California would have to experience heavy rain and snow every other day until May to get the state back to its average annual precipitation totals, according to the Department of Water Resources.

“These actions will protect us all in the long run,” Cowin said during a news conference that included numerous state and federal officials, including those from wildlife and agricultural agencies.

Friday’s announcement came after Gov. Jerry Brown’s official drought declaration in mid-January, a decision that cleared the way for state and federal agencies to coordinate efforts to preserve water and send it where it is needed most. The governor urged Californians to reduce their water use by 20 percent.