Cities and water districts serving 19 million people in Southern California face smaller water deliveries this summer under a plan approved by the region's water wholesaler in response to ongoing dry conditions.

The Metropolitan Water District, which sells imported water to more than two dozen local agencies, voted Tuesday to slash regional deliveries by 15 percent as California grapples with a fourth year of drought.

The cutbacks, which take effect in July, were expected to spur communities to step up their conservation efforts to avoid paying for high-priced water beyond the allotted amount.

The effect of the cuts would vary between local water districts depending on their supplies and how much water they have saved so far.

Metropolitan officials have said limiting water deliveries was necessary to stretch dwindling storage supplies as summer approaches and could help cities meet Gov. Jerry Brown's order to reduce urban water use by 25 percent compared with 2013 levels — a first in state history.

California is in the grips of a multiyear drought that has dried up wells and forced farmers to leave land idle. Earlier this month, state surveyors found the lowest snow level in the Sierra Nevada snowpack in more than a half century of record keeping.

Several board members unsuccessfully tried to push for a deeper reduction in regional deliveries — 20 percent — to help preserve stored water.

"I'm still not convinced" the smaller cut is enough, said Judy Abdo, who represents Santa Monica.

The board agreed to revisit the issue in December and take further action if necessary.

It marked the fourth time wholesale water deliveries to Southern California have been curtailed. Cities that want to purchase more water would have to pay stiff penalties — up to four times the normal price — for extra deliveries.

Funds collected from the penalties would go toward conservation programs and boosting water supplies.

During the last drought of 2009 and 2010, water districts avoided paying for expensive water.