SACRAMENTO, Calif. — California water regulators adopted sweeping, unprecedented restrictions on how people, governments and businesses can use water amid the state’s ongoing drought, hoping to push reluctant residents to deeper conservation.

The State Water Resources Control Board approved rules Tuesday that force cities to limit watering on public property, encourage homeowners to let their lawns die and impose mandatory water-savings targets for the hundreds of local agencies and cities that supply water to California customers.

Gov. Jerry Brown sought the more stringent regulations, arguing that voluntary conservation efforts have so far not yielded the water savings needed amid a four-year drought. He ordered water agencies to cut urban water use by 25 percent from levels in 2013, the year before he declared a drought emergency.

“It is better to prepare now than face much more painful cuts should it not rain in the fall,” board Chairwoman Felicia Marcus said Tuesday as the panel voted 5-0 to approve the new rules.

Although the rules are called mandatory, it’s still unclear what punishment the state water board and local agencies will impose for those that don’t meet the targets. Board officials said they expect dramatic water savings as soon as June and are willing to add restrictions and penalties for agencies that lag.