SAN DIEGO -- Officials said Wednesday that Southern Californians are running out of water and insuring adequate future supplies will depend on solving environmental concerns on the Sacramento-San Joaquin Delta, making greater use of purified sewage water, building more desalination plants and improving conservation efforts.

Those recommendations came in the last of four Southern California meetings to plan the area's water needs for the next two decades. Attending were 160 Southern California water officials, businesses, environmental and community leaders.

Everyone agreed the state's water system is inadequate but participants questioned whether Californians could muster the political will to enact any major changes. A desalination plant under construction in Carlsbad was vigorously opposed by environmentalists and voters have rejected several proposals over the years to clean sewage water to drinking-water standards.

Metropolitan Water District, Southern California's biggest water wholesaler, called the meeting Wednesday to get advice on updating its water resources plan through 2030. It was the last of four such meetings. Earlier meetings were in Newport Beach, Ontario and Los Angeles.

Solving environmental problems on the Sacramento River emerged as the most urgent concern at the gathering. Water shipments to Southern California have been cut from the Delta to protect an endangered fish.

"Unless we fix the Delta, nothing else will work," said Jeff Kightlinger, Metropolitan's general manager. But legislators have failed for decades to reconcile competing interests and find a solution to get more water from the inland waterway.

The other main source of water, the Colorado River, can't be relied upon to deliver as much water as it has historically, Kightlinger said.

"We have had the driest eight-year period on the Colorado River in its entire recorded history," Kightlinger said. Moreover, climatic projections indicate that such periods will be increasingly common in coming years, he said.

Taken together, these trends indicate that imported water is going to be an increasingly unreliable supply in the future, Kightlinger said. And most water consumed in Southern California is imported. In San Diego County, 80 percent to 90 percent of the water is brought in from elsewhere.

Kightlinger offered some comfort, telling the audience that Southern California is in a far stronger position to weather drought than it was during the last one, in the late 1980s to early 1990s. At that time, the area had just 300,000 acre-feet in storage, he said. Now, 2 million acre-feet is in storage.

About one-fourth of that water is in Diamond Valley Lake, a reservoir near Hemet completed by Metropolitan in 1999 that has a capacity of 800,000 acre-feet. An acre-foot is about 326,000 gallons, or enough to supply six to seven people for a year, Metropolitan said.

Those attending include representatives of local water districts throughout the county, and the San Diego County Water Authority, which imports water that's delivered to farmers and the local water districts, who sell directly to residential and business customers.

Reclamation needs more emphasis, said James Bond, an Encinitas city councilman who also is a board member of Metropolitan and the County Water Authority. "It takes political will and courage," to overcome opposition from members of the public who are squeamish about drinking reclaimed water, Bond said.

Metropolitan officials said the advice from the meetings will help it revise its Integrated Resources Plan to get the right mix of approaches to meet Southern California's water demand, including conservation, reclamation, ground water and ocean desalination. Suggestions from all four meetings will be considered by Metropolitan's board later this year.

The revised plan is expected to be ready next year.

For more information about Metropolitan, visit its Web site at www.mwdh2o.com.

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.