According to San Diego County Water Authority records, the agency chalked up its second highest July water sales in six years in 2007 - just a month after asking residents to cut water use by 20 gallons a day.

Officials say it's too soon to tell, but these wholesale water sales figures suggest that many local residents may not be paying much attention to calls asking them to cut back water use because of looming supply shortages.

As San Diego County's regional wholesaler, the Water Authority supplies nearly all of the water that pours out of county residents' taps, flows to businesses, fills tubs, toilets, and washing machines and waters lawns, gardens and landscapes. The agency buys water and sells it to 24 member cities and agencies.

In addition to the July sales, the Water Authority's August water sales were its highest in history for the month since it started keeping records - more than 26.8 billion gallons. And local water demand through October is 6.6 percent higher than it was in October 2006.

Meanwhile, officials from the Los Angeles-based Metropolitan Water District said its water sales also are high despite a water-conservation campaign. Metropolitan is Southern California's main water wholesaler, selling water to nearly 18 million people represented by 26 cities and water agencies, including the Water Authority, in six counties.

However, Brandon Goshi, a Metropolitan analyst and manager, said water-sales numbers could be affected by many variables, from retail billing practices to buying water to store rather than use, weather changes and population increases. He said because of that, it was not possible to say that increasing sales meant that people were ignoring conservation calls.

Last week, Water Authority board members voted to spend $206,000 on a "more aggressive" public conservation campaign. Spokesman John Liarakos said the money could include hiring an advertising consultant, increasing TV and video marketing and sending staff representatives to community events.

Water agencies across the state - including Metropolitan - have started public campaigns asking people to cut water use because drought and environmental worries have the state on the brink of its worst water supply shortages since the 1987-91 drought.

Historically, Southern California has relied on two main sources for its life-sustaining imported water: the Colorado River and the State Water Project, the latter a 600-mile series of dams, reservoirs and pumps that sends Northern California rainfall and snowmelt to the rest of the state.

Supplies from both are threatened. The Colorado River watershed is in its eighth year of drought. And in September, a federal judge issued an environmental ruling that will cut back the State Water Project's powerful pumps in 2008 in order to protect an endangered fish.

Ken Weinberg, resource manager for the Water Authority, said there were signs that San Diego County residents were responding to the calls to cut water use.

Weinberg said the agency's water demand was lower in September and October than in 2006. But he said water officials are not sure how to measure October's figures because hundreds of thousands of residents were forced out of their homes -- and away from their regular water-use patterns -- when evacuated during the firestorms.

Weinberg also said that the agency had conducted telephone surveys that indicated that local residents were at least aware of the conservation messages.

"I think they're getting the message," Weinberg said. "It takes time to change patterns of behavior."

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