California’s snowpack testing on Wednesday was more encouraging than last year, but officials were far from certain that the drought was ending. And the prolonged drought has laid bare the patchwork way water is parceled out.

Farmers here have become a target not just of city dwellers forced by conservation decrees to shorten showers and let their lawns go brown, but also of other farmers. In the Sacramento-San Joaquin River Delta in Northern California this year, growers grudgingly cut production to free up water for Central Valley farms, driven less by charity than by fear that the state would demand even more water if they did not.

But while California’s farmers could conserve more — fewer than half use low-flow irrigation methods — the reality is more complex. Agriculture makes up just 2.2 percent of California’s economy, but this area remains the nation’s green grocer, and farming is still the economic lifeblood of the state’s arid center. Both locally and nationally, farmers pack a political punch well above their weight.

“The federal government’s involvement in water is more influenced by what goes on with Westlands than any other single entity,” said Daniel P. Beard, who was the commissioner of the Interior Department’s Bureau of Reclamation — the agency overseeing Western water — under President Bill Clinton. “They’re not wrapped around the axle on politics or ideology; they’re pragmatists. What they want is water, a continuation of the flow of money from agricultural programs, and more water.”

And for good reason. Since 2005, on average, Westlands farms have annually sopped up one and a half times as much water as all of Los Angeles, most of it — some years, almost all of it — from federal deliveries. The water, largely siphoned from the Sacramento River Basin in Northern California, fuels a prodigious harvest, reported to be more than $1.5 billion last year: almonds for export; tomatoes for paste and sauce; wine grapes; cotton; produce sold under labels like Heinz and Dole.