LAKE ELSINORE -- The warning was anything but watered down.

Residents, businesses, local governments and the state will have to cut Southern California's demand for water and improve its supply, the top executive at the state's largest water agency told local leaders Thursday morning.

As federally protected fish in the Sacramento-San Joaquin river delta are chewed up by the thousands, a judge ordered limits on pumps there. The move is expected to cut water deliveries from Northern California by one-third in coming months.

Southern California depends on the Sierra snow melt for roughly half of its water, and farmers here already are feeling the impact, as some say they may have to rip out fruit trees.

Jeff Kightlinger, general manager of the Metropolitan Water District of Southern California, said the situation isn't going to get better on its own, especially if the region adds an expected 7 million residents during the next two decades.

Lighter snowfall in the Sierras has made seven of the last 10 years among the driest on record, Kightlinger said. Though his agency has so far coped through efficiency and better storage capacity, he said, the region now must take more dramatic measures in conservation, efficiency and importing.

"We can't live in a world where we're short of water 70 percent of the time and still make our economy work," Kightlinger told several dozen civic and business leaders at The Diamond stadium complex in Lake Elsinore. "This really is a time when we're going to have to pull together as a water community."

For a venue where most breakfast meetings are for networking with local chamber of commerce members, the 7:30 a.m. confab drew an unusually large number of elected officials, some from as far away as Riverside and Valley Center. City council members, developers and state legislators will all have a role to play in conserving water, Kightlinger suggested.

Kightlinger's warning Thursday came as the days tick down to a deadline for shoring up levees and pumps in the delta. State officials have called for borrowing billions of dollars for water infrastructure. Democrats and Republicans in Sacramento have been unable to agree on the details, however, and appear likely to miss Monday's deadline to put a bond on the Feb. 5 ballot.

State Assemblyman Kevin Jeffries, R-Murrieta, said he expects any such bond vote to be pushed back until at least June unless legislative leaders call an emergency session this weekend.

"The Republicans are the ones saying we need more water, and the Democrats are the ones saying 'Buy another brick for your toilet,'" Assemblyman John Benoit, R-Palm Desert, told the group.

Another sticking point is that a leading Democratic bond proposal includes additional groundwater storage, while a top GOP proposal calls for three new above-ground reservoirs in the Central Valley.

Kightlinger said either of those two options could go a long way to improving Southern California's supply. Regardless, he said, a solution will require changes in both supply and demand.

"This ought not be ideological," Kightlinger said.

Contact staff writer Chris Bagley at (951) 676-4315, Ext. 2615, or cbagley@californian.com.