Water deliveries to more than two dozen cities and agencies serving 19 million people in Southern California could be curtailed under a plan proposed by one of the state's largest water wholesalers amid severe drought.

The board of the Metropolitan Water District was set to meet Tuesday to consider slashing regional water deliveries by 15 percent beginning in July. The district serves parts of Los Angeles, Orange, San Diego, Riverside, San Bernardino and Ventura counties.

The effects of the cuts would vary between local water districts. Places that have done a poor job of conserving would have to crack down on outdoor watering and take other conservation measures and boost water rates to avoid paying a high price for extra water.

A day earlier, a board committee recommended reducing deliveries as the drought drags on. Several members wanted a deeper cut in deliveries — 20 percent — but were outvoted by others who feared it could hurt the economy.

Businesses "could be scrambling for the hills" if the reduction was steeper, said Michael Touhey, who represents the Upper San Gabriel Valley Municipal Water District.

California is enduring a fourth year of parched conditions, prompting Gov. Jerry Brown earlier this month to call for a mandatory 25 percent cut in urban water use compared with 2013 levels.

To meet Brown's goal, the State Water Resources Control Board released draft reduction targets for more than 400 water agencies that must cut their water use by anywhere from 10 percent to 35 percent. The targets are based on per-capita water use.

The MWD's general manager, Jeffrey Kightlinger, said limiting water supplies to member agencies is necessary to meet demand and stretch storage reserves, which currently stand at about 1.2 million acre-feet, less than half of what was in storage at the end of 2012.

MWD officials said the proposed water delivery restrictions — along with conservation, rebate programs and other tools — could help local water districts meet the governor's goal. The cuts would stay in effect for a year.

The agency noted that it has a proven record of aggressive water conservation. Per capita water use in Southern California has declined by about 24 percent since 1990, even as the region's population grew by 5 million, and it has spent $750 million over 25 years on water use efficiency.

Last year, the MWD delivered 2.1 million acre-feet of water and will supply 300,000 acre-feet less this year under the proposal. An acre-foot is enough to cover an acre with a foot of water, or meet the annual needs of about two households.

Cities that need more water would have to pay a penalty — up to four times the normal price — for extra deliveries.

The proposed tightening of water supplies comes as state surveyors earlier this month found the lowest snow level in the Sierra Nevada snowpack in 65 years of record keeping.

The MWD, which imports water from the Colorado River and Northern California to supplement local supplies, was most recently forced to slash water deliveries during the previous drought in 2009 and 2010. Water districts back then lived within their means and didn't end up purchasing expensive water.

During Monday's deliberations, committee members representing Beverly Hills, San Diego and several other cities favored a deeper reduction in water deliveries, saying it's necessary to maintain storage reserves.

"We don't know when this drought is going to end," said Robert Wunderlich, who represents Beverly Hills.

The board committee agreed to revisit the issue if drought conditions worsen that would require limiting deliveries even more.