It’s hard to know how much to panic over California’s dwindling water supplies. The state has never really had enough water, after all, yet lawns in Beverly Hills somehow remain perpetually green. Earlier this month, however, came a sign that life might soon be getting more uncomfortable for more Californians.

On Aug. 3, the State Water Resources Control Board voted 5 to 0 to issue an “emergency curtailment” order for the Sacramento-San Joaquin Delta watershed. Last week the order was submitted to the state’s Office of Administrative Law, which is likely to approve it.

The watershed covers about 40% of the state, stretching roughly from Fresno to Oregon, and is California’s largest source of surface water. About 5,700 holders of water rights, largely in agriculture and business, will be affected by the reduction in water access. Although many farms have already drawn most of the water they need for the season, the board’s move was a sign that ancestral water rights won’t be a guarantee of actual water if drought persists.