California faces a cutback of water from the Colorado River unless a water sharing agreement is in place by Tuesday, December 31. The state would lose enough water to supply one million people a year in Los Angeles, San Diego and the California desert.

Last week, the Bush administration announced that California's share of water from the Colorado River, a major source for the drought parched West, would be reduced, to ensure supplies for other Western states.

"The six western states that share water in the Colorado River with California have been after California for years to use only its allotted amount," Rita Sudman of the Water Education Foundation explained. "California has used water that is so-called surplus. The other states haven't been using it."

But now, growing states like Arizona and Nevada want to start.

California's proposed cutback of nearly 15 percent can be averted if water agencies in coastal San Diego and the inland Imperial Valley can reach an agreement. Colorado River surpluses have nurtured a $1 billion a year farming economy in the desert valley, and federal officials want them to share some water with San Diego.

Environmental concerns over an inland body of water have complicated talks, said Adan Ortega of the Metropolitan Water District of Southern California.

"The Imperial Valley interests would like some assurances that they will not be held liable in the event that there are later liabilities for the Salton Sea, which is a sea in southern California that is gradually dying," Mr. Ortega said. "And then secondly, San Diego wants to make sure that the deal is done in such a way that they can afford it. The rest of Southern California is watching closely because, tied to this deal, is the surplus of Colorado River water that we had been planning on to store over the next 15 years."

The official says, agreement or no agreement, California will survive. Conservation should help to make up any shortfall. "We have already planned for the eventuality that this deal doesn't go through simply because the Colorado River has been in a drought over the last four years, and so we have been anticipating that even if the political stars lined up, that we would not get the full surplus anyway," Mr. Ortega continued.

Water agency officials say San Diego and Los Angeles have a two year supply of water in reserve. But Rita Sudman says regional officials must make long range plans. "It really behooves the state of California and the parties involved in California to use the amount of water they are entitled to on the Colorado River," she said. "And look for [solutions, such as] voluntary transfers between agriculture and cities, conservation, reclamation."

Ms. Sudman says desalting seawater is another long range option to help California meet its water needs. She says the process, while expensive, can help some coastal cities.