California farmers’ voluntary proposal to reduce water consumption by 25 percent was accepted Friday, avoiding the threat of deep mandatory cuts amid one of the worst droughts on record.

Officials hope the deal will serve as a model for more such agreements with growers in the nation’s top-producing farm state, where agriculture makes up for 80 percent of all water drawn from rivers, streams and the ground.

"We're in a drought unprecedented in our time. That's calling upon us to take unprecedented action," Felicia Marcus, chairwoman of the state Water Resources Control Board, said in announcing the agreement.

The latest concession from farmers indicates the severity of the water shortage in the state, which is suffering through its driest four years on record.

California water law is built around preserving the rights of so-called senior rights holders – farms and others whose acreage abuts rivers and streams, or whose claims to water date back a century or more.

The offer potentially covers hundreds of farms in the Sacramento delta and San Joaquin rivers, the heart of California’s water system. About 25 percent of all California river water runs through the delta, according to the state’s Departments of Water Resources.

The farmers made the offer after state officials warned they were days away from ordering the first cuts I more than 30 years to the senior water rights holders’ allotments.

The state has already ordered cities and towns to cut their water use by 25 percent and has curtailed water deliveries to many other farmers. Many city dwellers and others have complained that agriculture should make more of a water sacrifice.

Rudy Mussi, whose family farms about 4,000 acres in the delta southwest of Stockton, reacted with mixed emotions about state approval of the deal.

"The 25 percent savings, that gives us certainty," Mussi told The Associated Press. "But at the same time I'm being asked to give up 25 percent of my paycheck."

Although delta farmers’ offers would not go far enough to save the shrinking waterways statewide, the more farmers sign on to the deal, the state could save significant amounts of water each year.

The agreement "is an illustration of creative practical approaches that water managers in the state of California are taking to help get us all through this devastating drought," said Michael George, state water master for the delta.

California produces nearly half of the fruits, nuts and vegetables grown in the country, but agriculture experts suggest they would expect only modest immediate effects on food prices from any reduction in water for the senior water rights holders.

Under the deal, delta farmers have until June 1 to lay out how they will use 25 percent less water during the summer. That could include irrigating their crops less or leaving some of their land fallow.

In exchange, the state gave assurances to the farmers it will not cut the remaining 75 percent of the water to which they are entitled.

"When your back is up against the wall, I guess you'll do anything," said Paul Wenger, president of the California Farm Bureau Federation and an almond grower in the Modesto-area, outside of the delta. He said he is skeptical the deal will protect the farmers if the drought worsens.

Senior water rights holders last saw their water cut in 1977, but that move applied only to dozens of people along a stretch of the Sacramento River.

Ellen Hanak, a water policy expert at the Public Policy Institute of California think-tank, said senior water rights holders don't necessarily face complete water cutoffs, as people with less venerable claims to water have endured.

"It's important for people to realize that there are haircuts that are partial — they don't necessarily mean shaving everything off," Hanak said.

Any accord with delta farmers would probably rely largely on the honor system. California currently does not require monitoring or meters for superior rights holders.

The Associated Press contributed to this report