PepsiCo Inc. is reducing the amount of plastic it uses to package its bottled water in the U.S., in the latest step by a beverage company to portray itself as environmentally conscious as bottled water sales slip. The new half-liter (16.9-oz.) bottle for Aquafina, the largest U.S. bottled water brand, weighs about 20% less than the one it is replacing, making it one of the lightest among bottled-water brands in the U.S. The Purchase, N.Y., company and its competitors have been besieged with criticism about environmental waste created by bottling a drink that people can get from the tap, particularly since only 24.6% of polyethylene terephthalate, or PET plastic bottles used for soda, water, and other products are recycled in the U.S., according to the National Association for PET Container Resources, an industry group. Many consumers also are cutting down on bottled water consumption and turning to the tap instead in the economic downturn to save money. U.S. bottled water sales slipped 0.4% in 2008 following years of double-digit growth, according to Beverage Digest, an industry publication. Beverage market researcher Canadean Ltd. predicts U.S. bottled-water growth of less than 1% a year for the next five years, due to the current economic turmoil and persistent environmental concerns. To try to quell the public criticism, and to cut costs, beverage companies have been steadily shrinking the weight of their PET plastic bottles. In 2007, Nestle SA's U.S. water unit reduced the weight of its half-liter bottle for regional brands such as Poland Springs to 12.26 grams. Coca-Cola Co. has also reduced the weight of its Dasani bottle. Pepsi's new Eco-Fina bottle weighs 10.9 grams, a little less than two U.S. quarters. It replaces a 13.7 gram bottle currently on the market and contains less than half the plastic of a 24-gram Aquafina half-liter bottle sold in 2002. Gigi Kellett, national director of a "Think Outside the Bottle Campaign" for Corporate Accountability International, an organization that urges consumers to drink tap water, said a lighter bottle is welcome. But she said she's concerned about "putting a green veneer on a plastic bottle." "Bottled water is costly for the environment, our pocketbooks and our public water systems," Ms. Kellett said. The price of a half-liter of Aquafina will stay about the same, despite the reduced amount of plastic, to help protect profit margins for the company and its bottlers at a time of declining volume, said Rick Gomez, chief marketing officer of hydration brands at Pepsi-Cola North America Beverages. Taking plastic out of bottles is a challenge for bottled water makers. Rob Le Bras-Brown, Pepsi's vice president of packaging innovation and development, said the company had to create a bottle with a thin "hydroskin" that was strong enough to hold up inside a gym bag and firm enough that water wouldn't spill out when squeezed. Pepsi designers created a skeleton within the plastic, where thicker plastic strengthens the base and the labeled mid-section. The new bottle features a rippled web pattern, with thicker plastic in the center where consumers wrap their fingers and thinner plastic on the neck and lower sides. "It has to feel lighter and more flexible, but it can't feel squishy," he said. "It can't feel like you're holding a bag."