LOS ANGELES - Southern Californians, fond of their private pools, golf courses, garden sprinklers and the ubiquitous car wash, are being urged to reform their water-guzzling ways after the region's driest year on record.

A mere 3.2 inches of rain -- less than a quarter as much as usual -- fell on downtown Los Angeles in the year beginning on July 1, 2006, the lowest since records began 130 years ago.

A hot summer of short showers is forecast to follow.

Rainfall totals were little better in other nearby cities, something experts say is a reminder that current water consumption levels seem unsustainable.

The water sources hundreds of miles away that transformed Los Angeles from a semi-arid town 100 years ago into the nation's second-largest city are also shrinking.

"We have a system that is at risk, especially if we continue to have population growth, putting people in dry places and figuring a way to overcome local water limits," said David Carle, author of "Water and the California Dream."

Local water sources would support a population of about 3 million in southern California. Yet 18 million people now live here.

The Eastern Sierra mountains, from where Los Angeles gets about half of its water supply, had its second-lowest snowpack on record this year. The Colorado River, whose waters are piped in via a 242-mile (389-km) aqueduct, is in its eighth year of drought.

Mandatory cuts are not envisaged for now, but officials have urged homeowners to cut water usage by about 10 percent, or 20 gallons a day.

"We have spent years preparing for years like this," said Andy Sienkiewich, resource implementation manager at the Metropolitan Water District (MWD) of Southern California, which serves some 18 million people.

"We have built up substantial water storage reserves, both underground and in surface water reservoirs. We have also invested heavily in waste water recycling and water conservation measures," Sienkiewich said.


Low-flush toilets and clothes washers that save up to 50 percent of water have resulted in huge savings over the years.

But the biggest challenge lies in Southern California backyards where home sprinklers keeping lawns lush and green account for as much as 70 percent of summer water use.

"What's growing in areas of Southern California is mostly not native vegetation. They have created urban forests of lawns and trees that are dependent on a whole lot of water," said Carle.

"I have seen sprinklers not only watering the grass but watering the road, the driveway and the sidewalk."

Over-watering -- not drought -- is the most common cause of plant deaths in Southern California gardens.

So-called "smart sprinklers" linked to satellite weather systems that adjust watering depending on forecast rain or clouds are on the rise.

More than 30 Los Angeles city parks are using the weather-based sprinklers but the cost and lack of mass retail distribution mean they have yet to gain widespread home use.

The MWD says it has had some success with training programs for homeowners, businesses and the building industry that encourage replacing lawns with drought resistant plants like cactus and rocks.

But water officials admit they have their work cut out for them trying to wean southern Californians off their passion for lawns.

In the last official California drought, from 1987-1993, some homeowners in Santa Barbara made headlines by painting their shriveled-up grass with green paint.

Carle said Southern California has a history of long droughts, one of them lasting 100 years, back to the 10th century.

But that was before mass population increases spurred by aqueducts built by Los Angeles engineer William Mulholland at the turn of the 20th century.