California’s first come, first served, water-rights system is about to be tested.

State water regulators are expected to issue curtailment orders to the most privileged water users in California – those with so-called senior water rights, claimed before the state established a permitting process in 1914. 

Those lucky enough to be grandfathered in, including corporations, farms and irrigation districts, usually don’t have much to worry about when it comes to water. They’ve been last in line for cuts in dry years, but the drought is starting to chip away at those historic privileges, says Stanford Law School’s Barton “Buzz” Thompson.

“California’s drought has now gone on for a long enough period of time, and it’s bad enough, that it looks like we might actually shut off our senior water rights holders,” Thompson says.

Some rural irrigation districts with senior rights may sue over the expected water cutbacks. Jeanne Zolezzi, a Stockton attorney who represents several irrigation districts with senior water rights, says she doesn’t believe the State Water Resources Control Board has the authority to shut them off. If regulators demand a curtailment, she insists, they need to hold a hearing and provide evidence of harm rather than simply issuing an order.