For the first time in its 54-year history, the State Water Project, a backbone of California’s water system, will provide no water to urban residents or farmers this year because of the severe drought, state officials said Friday.

The announcement does not mean that communities will have no water this summer. But it does mean that every region is largely on its own now and will have to rely on water stored in local reservoirs, pumped from underground wells, recycled water and conservation to satisfy demand.

Silicon Valley and parts of the East Bay — particularly residents of Livermore, Pleasanton and Dublin, who receive 80 percent of their water each year from the State Water Project — will feel the impact the most in the Bay Area.

Hardest hit, however, will be the state’s huge agriculture industry.

“We expect hundreds of thousands of acres of land in the Central Valley to go unplanted,” said Paul Wenger, president of the California Farm Bureau Federation. “That will cause severe economic problems in our rural regions — loss of jobs and economic activity, with all the heartache that entails.”

The state’s decision to turn off its main spigot will be re-evaluated every month and could change if California sees significant rainfall in February, March and April, state water officials said at a Friday morning news conference.

Still, the news highlighted how California is in uncharted territory this year. Last year was the driest in the state’s recorded history back to 1850. The Sierra Nevada snowpack is at 15 percent of normal, even after a storm this week. And January set more records for lack of rainfall.

“Today’s action is a stark reminder that California’s drought is real,” said Gov. Jerry Brown. “We’re taking every possible step to prepare the state for the continuing dry conditions we face.”

Bay Area impact

The State Water Project, approved by voters in 1960 and a key legacy of former Gov. Pat Brown, the governor’s late father, is a massive system of 21 dams and 701 miles of pipes and canals that moves water from Northern California to the south. It essentially takes melting snow from the Sierra Nevada, captures it and transports it from Lake Oroville in Butte County through the Sacramento-San Joaquin River Delta all the way to San Diego. In doing so, it provides drinking water for 23 million people from Silicon Valley to the Los Angeles basin and irrigates about 750,000 acres of farmland.

In November, because of the drought, officials at the state Department of Water Resources announced that summer water deliveries from the project would be only 5 percent of the amount that the farms and cities who buy water from the project have under contract. By comparison, the project allocated 35 percent last year and 65 percent in 2012.

But even that proved to be too optimistic.

“Simply put, there’s not enough water in the system right now for customers to expect any water this season from the project,” said Mark Cowin, the department’s director.

There are 29 water districts in California that receive allocations from the State Water Project, including the Santa Clara Valley Water District, the Metropolitan Water District in Los Angeles and the Alameda County Water District.

“We anticipated this was a distinct possibility,” said Marty Grimes, a spokesman for the Santa Clara Valley Water District. “It makes a challenging year even more challenging.”

The Santa Clara Valley Water District board voted this week to ask its 1.8 million customers to cut their water use by 10 percent voluntarily. The district has a year’s supply of water stored in underground aquifers in Santa Clara County, nearly another year’s supply banked underground near Bakersfield, and a $50 million recycled water plant under construction in Alviso to provide up to 10 percent of the county’s water demand when it is finished in May. It also has 10 local reservoirs that are 32 percent full.

The roughly 200,000 residents of Livermore, Pleasanton, Dublin and part of San Ramon who are under the authority of the Zone 7 Water Agency will take a bigger hit.

By pumping more groundwater, the district will have sufficient water to meet basic health and safety needs, said board President Bill Stevens. But reductions for other purposes may be necessary, he said. The agency accelerated plans to build two new wells, and owners of some vineyards in the area are concerned that water shortages could damage their crops.

Another 330,000 residents of Fremont, Newark and Union City receive 40 percent of their water from the State Water Project.

“It’s a big deal,” said Robert Shaver, assistant general manager of the Alameda County Water District. “Our planning is based on 1977, which had been the worst year ever. This year is worse.”

Shaver said the district will pump more groundwater, buy more water from the Hetch Hetchy system and already has asked residents for 20 percent conservation, as has Zone 7.

Other Bay Area communities are not affected because they receive no State Water Project water. They include Marin County, Santa Cruz County and customers of the East Bay Municipal Utility District and the Contra Costa Water District. Also not affected are the 2.6 million residents served by the San Francisco Public Utilities Commission in San Francisco, San Mateo, Santa Clara and Alameda counties, who receive Hetch Hetchy water.

Other tough actions

Meanwhile Friday, state and federal officials also announced they will withhold water from three reservoirs in Northern California that normally would be released to provide fresh water for salmon, smelt and other fish in the Delta.

The release of that fresh water also helps reduce salinity in the Delta, ensuring better quality drinking water for the Bay Area and other regions. The reservoirs — Oroville, Shasta and Folsom — are now releasing a combined 5,050 cubic feet per second for fish and drinking water quality. They will continue doing that, but will not release an additional 2,000 cubic feet per second as had been planned.

State officials also announced Friday that they will curtail 5,800 junior water rights holders in the Central Valley — nearly all farmers — from diverting water from streams. In many cases, they can pump groundwater to make up the difference.

Federal officials who run the state’s other large water system, the Central Valley Project, have not yet made an allocation announcement, but are expected to by mid-February, and that number also will be very low, further impacting farmers and some cities.

Staff writer Denis Cuff contributed to this story. Paul Rogers covers resources and environmental issues. Contact him at 408-920-5045. Follow him at Twitter.com/paulrogerssjmn.