Along with providing around half of the nation's fruits and vegetables, Central Valley farms generate tens of billions of dollars in revenue annually. The Environmental Working Group estimates that California farmers have received more than $10 billion in subsidies since 1995. Indeed, California farmers achieved their regional economic and political dominance largely through government largesse and publicly financed, gargantuan water projects, such as the State and Central Valley Water Projects, which funnel huge quantities of water (as much as 80 percent of the state's overall supply, by some estimates) to the area.

And yet, the industry has spent millions on lobbying and a public relations campaign that portrays itself as the victim of over-regulation and water policies aimed at its destruction. For years, local farmers have protested reductions in water deliveries to the area from the San Francisco Bay Delta -- posting signs along the roadside with messages such as CONGRESS CREATED DUSTBOWL and FOOD GROWS WHERE WATER FLOWS. Similarly, a pack of pro-agriculture groups has railed against AB 685. Opponents, including the Western Growers Association -- a trade group that represents California farmers -- and the state's Chamber of Commerce, offered up a litany of criticism, warning that the law could, among other things, prevent local districts from shutting off water to non-paying customers, create subsidies for poor residents, and expose farmers and water districts to lawsuits. "A new 'right to water' in California law could potentially upset decades of legal precedent and could cost the State of California untold amounts of money," the Association of California Water Agencies wrote Gov. Brown, strongly urging a veto.

Supporters of AB 685 included numerous environmental groups, such as the Sierra Club and the California League of Conservation Voters, but the on-the-ground effort was headed by the Visalia-based Community Water Center and la Asociación de Gente Unida por el Agua, or AGUA, a group made up of local representatives from towns with contaminated water. "Part of the reason we're in the situation we're in, is because communities have been segregated and isolated," says Firestone, whose Community Water Center helped organize the AGUA coalition, many of whose members work in the very farm fields generating the pollution. "They're now speaking with a unified voice."

AGUA's efforts are in many ways reminiscent -- even an extension -- of the grassroots organizing of Cesar Chavez and The United Farmworkers Union. That group's famous rallying cry, "Sí, se puede" ("Yes, we can"), galvanized the movement that drew national attention to the often-terrible working conditions faced by California farmworkers.

On a March evening, just off Visalia's main drag, around 40 people crammed into the living room of the small bungalow that serves as AGUA's main offices, discussing strategies for an upcoming rally and meeting with legislators in Sacramento.

One AGUA representative, Sandra Garcia, 48, who picks fruit and vegetables near her hometown of Poplar, shook her head when I asked if she worried her activism might land her in trouble with her employer. "We have no choice," she says. "A few years ago, my boss said, 'I don't want you out stirring everyone up.' I told him, 'I'm trying to keep you from getting sued.' "

In rapid and impassioned Spanish, the group discussed the need to press state representatives about securing grant money to improve the water supplies of disadvantaged communities. Applying for the funds -- available through Proposition 84, a 2006 bond act funding safe drinking water initiatives -- is a complex process, requiring input from engineers and technical experts that the towns most in need often lack the funds to hire.

Such are the problems with the new law. In spite of AB 685's bold rhetoric, it does not actually require state agencies to do anything new. Though it mandates that state agencies take a "multi-agency" approach and consider the policy when they adopt or revise regulations, it does not require California to provide clean water or to allocate "additional resources" to fix ailing water systems. Nor does it require the agencies that oversee public water systems -- the Department of Water Resources, the State Water Resources Control Board and Department of Public Health -- to increase enforcement.

Nonetheless, local activists call AB 685 an important, if largely symbolic, first step toward greater recognition of the connection between clean water and human health. Firestone says AB 685 makes "a problem that was invisible into a priority. People have to pick up that rock and see the disparities around water in our state," she says. Debbie Davis, community and rural affairs adviser for the governor's office, agrees. "The bottom line is that the legislation spells out our intent, which is that everyone in the state should have access to safe water for basic human needs," says Davis, who worked as a community water activist before joining the governor's office. "In California, that should be a reasonable, minimum expectation."