NORTH COUNTY -- It's still a polite request, and not a demand. But the historically quiet call for people to find ways to use less water is about to get a little noisier.

Last week, Southern California's main water supplier, the Los Angeles-based Metropolitan Water District, voted to quadruple its spending and mount a $6.3 million campaign to urge people to, among other things: take shorter showers, stop overwatering lawns and gardens, install sprinkler controllers, fix leaky irrigation systems, and replace lawns with low-water-using plants.

And, while regional water officials say the region has plenty of water to get through this summer, Metropolitan is not alone in its call.

Long Beach officials last week issued an urgent call for its residents to cut water use; people in the San Francisco Bay Area are already conserving; and San Diego County Water Authority officials said they're planning a campaign to ask people to cut their use by 20 gallons a day.

The reason for the conservation call is simple. Southern California's main water supplies this summer appear to be starting to dry up.

The region in general, and the Los Angeles area in particular, is suffering through a severe single-year drought. The Colorado River, one of Southern California's two main sources of imported water, is in its eighth year of drought. And state water and Fish and Game officials stunned regional water leaders May 31 by abruptly shutting down the pumps that deliver Southern California's other imported water -- rain and snowmelt sent from Northern California through the State Water Project -- to protect an endangered fish, the delta smelt.

Friday afternoon, state officials announced they planned to ramp back up to full pumping to Southern California by today.

Jeff Kightlinger, Metropolitan's general manager, said the agency still believed that it would get all of the State Water Project water Southern California was slated to receive before the shutdown.

But officials say they're still worried that another dry year, or more shutdowns, could wreak havoc next year and beyond.

Voluntary or mandatory?

Water leaders said last week that despite the threats to regional water supplies, they weren't inclined to push for mandatory cuts for several reasons.

Most importantly, they said, the region has a lot of stored water that can sustain it for the immediate future. Kightlinger said last week that in 1991 -- the height of California's last major multiyear drought -- the agency had only about 250,000 acre-feet of backup water storage.

"Now we have a little over 2.5 million acre-feet," he said.

An acre-foot of water is roughly 325,900 gallons, enough to sustain two households for a year.

Other water leaders said that implementing mandatory water rationing could have a chilling effect on businesses, and the economy that relies upon a stable water supply.

"You don't want to create an economic panic if there's no need for it," Greg Quist, a longtime North County water official, said.

Kightlinger and others also said that implementing mandatory cuts while there were still backup supplies could impose needless sacrifice. After all, Mother Nature could still bail the region out.

"For all we know, it could be a wet year next year," Kightlinger said, referring to the fact that despite seemingly lengthening droughts and uncertainty, the heavens could open up and drench Southern California with rain and the Sierra Mountains with snow that could make most of the current water problems disappear next year.

For example, in 1991, in San Diego County, water leaders were poised to implement 50 percent cutbacks when the sky suddenly opened after five years of drought, pouring down more than 6 inches of rain in what was dubbed "Miracle March."

Other officials said the public would be less than happy if they endured mandatory cutbacks while there was ample storage, only to have the rain and snow finally reappear before supplies ran out. The public could blame water leaders for mismanaging the system.

Even worse, they could lose their trust in the water system, one official said.

George Loveland, who spent six years on the San Diego County Water Authority board before retiring 2 1/2 years ago, said if water agencies implement mandatory cuts too soon, the public could think that water officials "were crying wolf" -- and then ignore future calls for voluntary conservation.

Environmental groups such as the Sierra Club have pushed water agencies for years to increase calls for conservation, and continue to do so, whenever water leaders ask to build new dams and reservoirs that would increase backup storage.

But even it said last week that it did not find fault with water leaders' decision to make their conservation calls voluntary, rather than mandatory, in the current situation.

"I think we need to trust our water purveyors," said Bill Allayaud, the California Sierra Club's legislative director.

Looming

Still, the system seems to be cracking, and water officials appear more worried about the region's water supply future than they have for years.

That is due in part to the state's recent shutdown of the pumps that send water from Northern California south.

Kightlinger and others said the most worrisome part of the State Water Project shutdown was that it was not because of a natural drought, but because of a "regulatory" drought -- created to save the fragile Sacramento-San Joaquin Bay Delta ecosystem. He said real and regulatory droughts may not hurt Southern California this summer. But if they reoccurred, they could lead to mandatory water rationing next year.

Kightlinger said that Metropolitan had already stopped using its current water supplies to restock its storage. It also expected to withdraw between 200,000 and 600,000 acre-feet from its backup supplies to sustain the summer demand.

Indoor, outdoor

Meanwhile, regional and local water officials said that even though Californians had actually done a lot since the 1991 drought to conserve -- there is still plenty of room for people to cut back even more.

San Diego County Water Authority officials said that during the last 16 years, Californians had cut indoor water use drastically by installing low-flow shower heads, improved toilets and other devices.

However, officials said, as much as 60 percent of residential water use is outdoors -- and that now the push will be for people to cut that by planting low-water-using plants, improving irrigation systems and the like. Metropolitan and the Water Authority have already had Web sites for a number of years offering people tips on how to save water -- indoors and outside.

Metropolitan officials said the current calls for conservation were a gentle reminder that water in the West is a precious resource.

But Ken Weinberg, water resources manager for the Water Authority, said that people in the region needed to "rethink our lifestyles."

"The major message in long-term conservation is that we don't live in an area that can support the kind of landscapes that we have," he said. "We are talking about lifestyle changes. We're not saying it all has to be rocks and cactus, but we have to be making smarter, more efficient choices."

Contact staff writer Gig Conaughton at (760) 739-6696 or gconaughton@nctimes.com. Comment at nctimes.com.

People who would like to learn about how they can cut their water use can go to:

www.bewaterwise.com.

www.sdcwa.com.

www.thegarden.org.

www.laspilitas.com.

www.treeoflifenursery.com.