As California regulators vote to impose water rationing today, a new study estimates that the state’s epic drought will cost farmers $2.2 billion this year, while 17,100 agricultural workers will lose their jobs. But the worst may be yet to come.

“We’re in a critically dry this year,” said Jay Lund, a researcher at the University of California, Davis, and a coauthor of the report, at a press conference Tuesday. “There’s a very good chance next year will be dry or critically dry.”

Much of California’s $46 billion agricultural industry relies on rain and snowmelt for irrigation water delivered through a vast network of canals. With those supplies drying up, farmers have been pumping groundwater at a rapid clip to water their crops. The researchers estimate that groundwater may account for 53 percent of farmers’ water supply in 2014, up from 31 percent in a typical year.

“The ability to increase groundwater pumping as a substitute for decreased surface water supplies is critically important to California’s ability to cope with drought,” the report states.

But groundwater reserves replenish at slow rates, and if the drought persists in 2015 and 2016, farmers and city dwellers will start to pay the price, both in severely depleted water supplies and in energy costs to power those pumps.

“As groundwater levels drop, the costs to extract groundwater increase,” according to the report. “In some areas, water levels can drop below the installed capacity of existing wells, causing wells to go dry and reducing groundwater pumping capacity for subsequent drought years.”

The big problem: California, incredibly, does not regulate or even monitor groundwater pumping. “We’ve been really flying blind as regards to groundwater,” said Richard Howitt, a lead researcher on the study. “We have no idea who’s exactly using what.”

“We’re walking around signing checks without even balancing the checkbook,” he added.

That lack of data is hobbling the other way California deals with drought: water markets that allow farmers to buy water from other growers or cities. If buyers and sellers don’t know how much supply is on hand, pricing becomes a guessing game.

So some farmers are paying $1,000 to $2,000 for an acre-foot of water—the amount of water that will cover an acre of land at a depth of one foot. That’s triple what growers paid during the 2009 drought, according to Howitt.

“The anxiety level of the farm constituency is very high,” Karen Ross, secretary of the California Department of Food and Agriculture, said at the press conference.

To put it mildly. Farmers this year have taken 410,000 acres of land out of production and have started to abandon water-intensive crops such as cotton. (So far, food prices have not risen appreciably, the researchers said.)

So what’s to be done? First, lawmakers need to start regulating groundwater withdrawals and require farmers to report what they use. Technology can help as well. The UC Davis researchers said satellites can calculate groundwater reserves and keep track of farmland that goes fallow.

But Californians will have to adapt to using less water. A lot less.

“It’s possible under climate change that our net water use will have to drop 15 to 20 percent,” said Howitt.