NEW YORK — Just say H-2-No.

That's what an increasing number of public officials, environmental advocates and restaurateurs are urging people to do when they're tempted to reach for bottled water.

Rather than spend their dollars on costly plastic containers of water, consumers should boot the bottle and turn on their taps, according to such officials as San Francisco Mayor Gavin Newsom, Salt Lake City Mayor Ross "Rocky" Anderson and Minneapolis Mayor R.T. Rybak.

Those three sponsored a resolution at last month's meeting of the U.S. Conference of Mayors calling for a study to examine the environmental impact that millions of empty water bottles have on municipal garbage operations.

Newsom and Los Angeles Mayor Antonio Villaraigosa have issued executive orders prohibiting the use of city money to buy bottled water, and the Ann Arbor City Council in Michigan last month approved a measure calling for city events to be bottled-water-free.

"For a long time, I've viewed (bottled water) as a huge marketing scam," Anderson said recently, explaining why he has called for city employees to drink tap water and use refillable water bottles.

IT'S CHEAP AND TASTY

Municipal water supplies are just as good as bottled water and are monitored far more closely, city officials nationwide say. And a gallon of tap water typically costs less than a penny, up to 10,000 times less than an equivalent gallon of bottled water, according to the mayors' resolution.

The bottled-water industry calls the attacks unfair. The head of the industry's leading trade group says bottled water's competition is not the kitchen faucet but the soft drinks, sports drinks, iced teas and other drinks that fill grocery store shelves.

"I think it's unfortunate there is now this tap water-versus-bottled water controversy," said Joseph Doss, president of the International Bottled Water Association, which represents 450 bottlers, distributors and suppliers. "We don't see it that way. I don't think consumers are replacing tap water with bottled water. We make a food product. We see other food products as our competitors."

Whether they're competing with Coke and Pepsi or the local water department, bottled-water companies have enjoyed strong sales growth since the early 1990s. A once-laughable idea — Who'd pay for water when you can get it for free? — has become the second-biggest category in the beverage industry.

Bottled water has been popular in many foreign countries for decades because of the poor quality of the local water supplies. The first brands to gain a foothold in the U.S. in the 1980s were imports such as Perrier and Evian, both from France, which were marketed as chic, trendy products.

Some water still comes from other countries, such as Fiji, but 97 percent of the bottled water sold in the U.S. is domestic.

BUSINESS IS BOOMING

Bottled water sales exceeded 8.25 billion gallons in 2006, a 9.5 percent increase over 2005, with sales of more than $10.8 billion. Americans drink, on average, 27.6 gallons of bottled water per person annually, up from 16.7 gallons in 2000, according to the Beverage Marketing Corp., a New York consulting firm.

That's a 65 percent increase. Only soft drinks outsell bottled water, and their market share has been gradually declining.

Although the bottled-water industry says its growth has not come at the expense of tap water, the amount of tap water that Americans drink has been falling.

New York City Health Commissioner Thomas Frieden believes a generation of younger Americans has grown up thinking that tap water isn't safe.

That was one reason he teamed with the city's environmental protection department to produce a $700,000 marketing campaign to urge New Yorkers to drink the city's tap water, which comes from the Catskill Mountains and often is cited as one of the purest water supplies in the country.

"Cool. Healthy. Clean. Zero sugar. Zero calories," one poster says. "NYC Water. Get your fill."

By stressing that water is calorie-free, Frieden hopes to persuade people to drink fewer sugary drinks as a way to reduce obesity. Whether that water comes out of a tap or is sold in a plastic bottle is of less concern to him.

But, he said, "If the popularity of bottled water leads to people thinking that tap water isn't safe, that's unfortunate because at least in New York, our tap water tastes better than any bottled water."

'ANOTHER ALTERNATIVE'

For environmental groups such as the Natural Resources Defense Council, the case against bottled water is clear. Manufacturing, transporting and disposing of plastic bottles consumes oil, contributing to global warming and filling up landfills. The council estimated that shipping the 43 million gallons of bottled water imported annually from the European Union creates about the same carbon dioxide emissions as 660 cars running for a year.

"When you factor in that water is something that is free and available to you, and then the oil and plastic that are consumed, and the transportation halfway around the world in some cases, bottled water becomes a product whose value isn't clear," said council spokeswoman Jennifer Powers. "I think there's a real thirst — no pun intended — on the part of people who want to play a part in doing something to help the environment, and this is one issue where there is another alternative."

But the bottled water association's Doss counters that plastic bottles are recyclable and that the amount of plastic used in the bottles has been reduced by 40 percent in the past five years. And water is not the only drink that is imported.

"There are thousands of other goods that are imported into the United States, that may be and are available in the United States," Doss said. "Do you want to drink a wine from Sonoma County, Calif., or do you want to choose a wine from another country? That should be a choice that a consumer has. Why should we be treated any differently than any other food product?"

But some restaurants see a difference between, say, an Italian wine and an Italian water. One of the biggest trends among high-end restaurants in recent years has been a move toward using locally grown meat and produce. A pioneer in that movement, Alice Waters of Chez Panisse in Berkeley, Calif., announced last year that her restaurant no longer would offer bottled water.

A handful of restaurants nationwide has followed suit, including New York's Del Posto, a joint venture of celebrity chef Mario Batali and restaurateur Joseph Bastianich.

The restaurant is installing about $20,000 in equipment that will turn New York tap water into still and carbonated mineral water. In the process, the restaurant will be sacrificing the hefty profits that come from selling a $2 bottle of water for $6 or $8.