LOS ANGELES — More Californians are questioning why giant bottled-water sellers continue to tap the state’s dwindling water supply during the worst drought in state history and are pressuring big retailers to stop using the scarce resource.

Courage Campaign, a non-profit online advocacy group, has collected more than 35,000 signatures to stop Wal-Mart, the world’s largest retailer, from sourcing water for its Great Value brand from Sacramento’s water supply.

Another 160,000 signed a petition to stop Nestlé from bottling groundwater at its five California plants.

“We haven’t seen this much passion from our members, haven’t seen this much energy since Prop 8 (ban on same-sex marriage, later overturned),” said Eddie Kurtz, executive director of Courage Campaign, which describes its mission as fighting for economic justice, human rights and corporate and financial accountability.

“We try to educate Californians and the drought is huge for us,” he said. “It has really hit home that we’re in crisis territory.”

This spring, Gov. Jerry Brown signed an executive order for the first mandatory drought restriction in California history, requiring cities to cut water use by 25 percent.

There are more than 100 water-bottling plants in California.

Wal-Mart buys its bottled water from DS Services of America, a large supplier that gets water from the Sacramento municipal water district, bottles it and sells it to various retailers.

Courage Campaign claims that buying water for 99 cents for every 748 gallons – the same rate charged commercial and residential users – results in huge profits when Wal-Mart turns around and sells it in bottles for 88 cents a gallon.

Wal-Mart does not agree. “Grossly inaccurate,” said Wal-Mart spokesman John Forrest Ales. “We’re one of several customers that use this supplier which purchases its water from the municipal district. We only buy about 10 percent of (DS Services’) products. Ninety percent goes to other businesses.”

The advocacy group’s calculations don’t take into account the supplier’s labor and business costs, how much it charges Wal-Mart and, in turn, Wal-Mart’s cost in getting bottles on shelves, Ales said.

“When you look at the overall use in California, bottled water accounts for 0.02 percent and that takes into account the water used” in manufacturing, said Chris Hogan, spokesman for the International Bottled Water Association, which represents the $13 billion U.S. industry.

It takes 1.32 liters of water to produce a one-liter bottle and "that’s an incredibly small water-use ratio,” Hogan said.

All manufacturing facilities use water, and agriculture accounts for 80 percent of water consumption in California. Hogan points out that water bottlers have an even greater stake in conserving water than other industries because they actually sell it.

“If the issue at hand is to talk about responsible water use, attacking what is probably one of the absolute smallest water-use footprint industry in the state seems a little odd,” Hogan said.

Americans drank 10.9 billion gallons of bottled water last year but that’s only three weeks’ worth of water consumed by Los Angeles Department of Water and Power customers, he said.

Industries try to minimize their impact, Kurtz said, but any use of such a scarce resource can jeopardize human beings and plant life.

“At the same time, Californians are being asked to dramatically reduce their water use,” he said.

The fact that Starbucks last week announced that it was voluntarily moving bottling of its Ethos water out of California is not helping the industry’s argument. Starbucks said it is suspending its operations in California during the drought as part of their mission to be globally responsible.

But Starbucks’ actual contribution to saving the environment by moving bottling to Pennsylvania has been questioned because the company will now have to ship the water more than 2,700 miles away.

Most of the water bottled in California is sold to Californians and some companies sell bottled California spring water (Calistoga Water, Palomar Mountain Spring Water, Mt. Shasta Spring Water), which can only come from California.

The outcry over water-bottling plants reflects growing scrutiny of the industry. A recent investigation by the Desert Sun, a Palm Springs newspaper, revealed that Nestlé had been taking spring water from the San Bernardino National Forest with an expired permit since 1988. The company, however, says it is allowed to operate pending permit renewal.

Peter Gleick, president of the Pacific Institute, wrote a book entitled “Bottled and Sold: The Story Behind Our Obsession with Bottled Water.” He argues that paying more for throwaway plastic when potable water is readily on tap is the result of fear-mongering by businesses that turned bottled water into the most successful product in a century.

On its website, Nestlé posted a question-and-answer interview with Tim Brown, CEO of Nestlé Waters North America.

Brown said that the company draws less than 0.008 percent of the state’s water and that closing their plants “won’t fix the drought.” Shutting down its water-bottling operations would save the state less than 0.3 percent of what the governor has asked residents to save, he said.

Wal-Mart’s Ales also points out that closing bottling operations would cost Californians because it would reduce jobs and tax revenues.

Nevertheless, Courage Campaign is organizing protests on Wednesday at Nestlé plants in Sacramento and in Cabazon, where Nestlé has an operating agreement with the Morongo Band of Mission Indians, which owns the water rights.

“There will be activists with signs and bullhorns,” Kurtz said. “We’re calling on the governor to really deal with this crisis. … We’re planning on escalating the call for a moratorium on all water bottling in California until the drought is over.”