From the Sacramento Bee (link below):

California’s drought regulators have lost a major lawsuit that could undermine their legal authority to stop farms and cities from pulling water from rivers and streams. An appeals court ruled that the State Water Resources Control Board lacks the power to interfere with “senior” water rights holders and cannot curtail their diversions of water from rivers.

Why some Californians have senior water rights

California’s water rights system is notoriously complicated but essentially boils down to how early a farm, city or other landowner claimed a water right.

The earlier someone claimed a right, the higher they are in the pecking order. Because the state board will first halt diversions from “junior” rights holders, having senior rights buffets a user from some of the agency’s curtailment orders.

The key date is 1914, when the California Water Commission Act took effect and the precursor to the state water board was established. Anyone holding rights that were claimed before 1914 is considered a senior rights holder.

Full article from the Sacramento Bee HERE.