Kenneth Nichols, water waste investigator for the Las Vegas Valley Water District, uses a video camera to document a "day of the week" violation Thursday morning at a Rebel gasoline station at 1080 S. Rainbow Blvd. In the winter, the business' assigned watering day is Wednesday. Photo by Clint Karlsen. Click image for enlargement.

The Southern Nevada Water Authority delivered more water to customers last year than it did in 2004, but consumptive water use in the Las Vegas Valley has remained about the same over the past two years, even while the population grew.

According to figures released Thursday by the region's wholesale water provider, almost 477,000 acre-feet of water was pumped from Lake Mead for delivery to valley homes and businesses in 2005, up nearly 10,000 acre-feet from 2004.

Despite the increase, water authority officials expect consumptive use for the year to come in right around the 2004 total of 265,000 acre-feet. In 2002, the valley's consumptive water use peaked at 318,000 acre-feet.

Consumptive use is the total amount of water delivered to customers minus the return-flow credits the authority receives for Colorado River water it puts back into Lake Mead as treated effluent.

Water used inside the house earns return-flow credits while water used outside does not.

Without the credits, the state's river allotment of 300,000 acre-feet a year would not be enough to meet water demand in Southern Nevada.

"What really makes the difference ... is controlling the amount of water people are putting on landscapes," said water authority spokesman J.C. Davis.

In an acre-foot are 325,851 gallons, roughly enough water to supply two Las Vegas Valley households for a year.

Water authority General Manager Pat Mulroy said she is encouraged by the year-end figures, but she worries that the gains made through conservation since 2002 might be tapering off.

"It's good news because despite the growth, water use didn't go up," Mulroy said. "It maybe also tells us we're plateauing."

The water authority board will hold a workshop next month to discuss whether to make permanent some or all of the current conservation measures, which were intended as a temporary response to the ongoing, six-year drought.

Board members voted Thursday to extend the region's second-stage "drought alert" status for another year.

Drought alert comes with such measures as assigned watering days and seasonal watering restrictions; tight water budgets for golf courses; development codes that prohibit grass in front yards and limit it in backyards; and programs that rebate money to people who replace their grass with desert landscaping.

The water authority counts the turf-rebate program among its greatest successes, but it seemed to lose momentum last year.

In 2004, 34 million square feet of turf were converted and $28.7 million in rebates paid in the Las Vegas Valley. The totals dropped to 15.4 million square feet and $14.2 million in rebates in 2005.

Since it was launched in January 1999, the rebate program has paid $55.8 million and eliminated 67.8 million square-feet of turf, enough to cover 1,177 football fields. The program is credited with saving some 3.7 billion gallons of water a year.

As for the increase in total deliveries during 2005, water authority officials blamed hotter, drier weather, especially later in the year.

The valley received no measurable rain in November and 0.02 inches in December. During the same two months in 2004, nearly 4 inches fell, 90 percent of the average annual precipitation.

"We've always said if you see rain, you're going to see a drop (in water use)," Mulroy said.

Though the authority hopes the community will embrace all of the agency's drought measures, Davis said the conservation ethic starts at home.

"If we could get residents to do one thing to help the water supply, it's watering only on their assigned days," he said. "Residents can have a huge impact by doing that."