Bottled water got a vote of no confidence last month, when a gathering of U.S. mayors passed a resolution encouraging cities to phase out government use of bottled water and to promote municipal water.

The guys at the Aqua Filter Fresh plant in Plum -- where neat rows of 5-gallon Tyler Mountain Water bottles roll steadily along an automated line to be tested, washed, even sniffed for quality assurance -- would like to invite a few of those officials for a visit.

"I wish the mayors and other people would come and see what we do," said Doug Hupe, executive vice president, as drivers zipped around him moving pallets stacked high with bottled water. He's ready to talk about the firm's standards, its recycling efforts, its service to customers who need the product.

As bottled water businesses go, this operation doesn't compare to the massive divisions run by Coca-Cola, Pepsi or Nestle. The local company's customers haven't begun shifting away from bottled into filtered systems or begun demanding an accounting of its efforts to be green.

But, like a slow leak that doesn't look serious at first but eventually could do some real damage, the burbling debate has been on the minds of the executives running the 35,000-square-foot plant that employs about 60.

America is having second thoughts about its love affair with bottled water. Environmentalists decry the use of plastic to package something that they say most people can get from the tap. Even consumers who prefer the taste of bottled water may reconsider as they watch their budgets shrink.

Just last week, the Phipps Conservatory and Botanical Gardens announced it had stopped selling individual bottles of water in favor of $2.25 sports bottles made of recycled plastic. The Oakland attraction installed a system that people can use to fill their bottles with municipal water that's been filtered.

"We're really hoping this is a trend that catches on," said Michael Sexauer, director of marketing and communications.

Earlier in the spring, the H.J. Heinz Co. moved into a new global headquarters at PPG Place and switched from providing bottled water to employees to a filtered system in which everyone has their own cup.

A new book, "Bottlemania," examines the growth of bottled water and Tappening, an activist venture by ad executives in New York, launched an anti-bottled water marketing campaign this spring funded in part by sales of reusable bottles.

Sales of bottled water had been growing for years. Beverage Digest, an industry trade publication, reported total bottled water sales last year hit $16.8 billion, up 14 percent, trailing only the $72 billion carbonated soft drink category. (Aqua Filter Fresh does not release financial information).

There are valid reasons, said John Sicher, editor of Beverage Digest. Bottled water is accessible and convenient. "It's a healthy, zero calorie beverage."

Growth has slowed so far this year, said Mr. Sicher, but that's as true for soft drinks as it is for water. "The whole beverage industry is stalling this year, largely because of the economy," he said.

Still, the steady drip of criticism over environmental concerns has not been ignored by the industry, which has switched to lighter weight bottles that use less plastic and rolled out programs to promote plastic bottle recycling.

It's not entirely clear what percentage of consumers are focused on the debate. Giant Eagle, which earlier this year began operating a bottling facility in Latrobe, has received a limited number of customer inquiries in recent months and most wanted to be reassured the company was using a recyclable plastic, according to a spokesman.

Bob Bell, president of Aqua Filter Fresh, remembers when bottled water came in heavy glass containers and there weren't a lot of companies selling the stuff. He worked for a company on the North Side before going out on his own.

The Tyler Mountain name started with a company in West Virginia. In a complicated arrangement, Mr. Bell owns a small percentage of that business and its owner has a percentage of his operation. The Pittsburgh-area business supplies the large, reusable bottles that the West Virginia operation needs. In addition, it supplies distributors in counties around Pittsburgh who have their own service areas.

About 80 percent of the Aqua Filter Fresh business involves taking water that the company buys from a spring in Maryland and treating it to remove anything beyond the minerals that give it flavor. A recent visit to the plant found pallets that held 40 5-gallon bottles each stacked up to the ceiling, as small loaders rushed around pulling freshly filled bottles off the bottling line.

A robot sent a steady supply of empty bottles through the line, where a machine shot forced air through each to check for cracks, then an employee leaned over to sniff each bottle for anything that didn't seem right. Next, rows of bottles were fed into an industrial bottle washer for a thorough cleaning.

From there, they went directly into a room where they were filled with water that had been on its own path through stainless steel pipes, filters and ultraviolet lights. A lab on site is set up to take samples for state-required tests and in-house checks.

Bottles coming through carried several different versions of the Tyler Mountain logo, even one that Mr. Bell identified as being from the early 1990s. The average bottle is used more than 50 times, he said.

Although the company supplies single-serve bottles to some customers, the bulk of its sales involve the larger bottles. Deliveries are split about half and half between offices and homes, with the company managing as many as 1,000 deliveries a day. (The Post-Gazette uses Tyler Mountain water).

Recent gas price hikes have put the pressure on to be efficient in making deliveries and spurred some investments in more fuel-efficient vehicles.

Aqua Filter Fresh claims to recycle anywhere from 50 to 400 bottles a day, grinding the light blue plastic containers, the caps, even the plastic pallets into materials that can be given second life in other products. Some recycling has been done for years. Other changes have come more recently.

In a move to head off questions about their practices, they're putting the finishing touches on a flier meant to explain their environmentally aware efforts to customers.

They've heard the jokes that those in the business really fill their bottles using a garden hose so they stand ready to organize plant tours for community groups. In addition to the bottled spring water, the plant also takes municipal water and treats if for clients who want a less expensive, purified water product. Distilled water is also available.

"I'll be the first to tell you I don't think there's anything wrong with Pittsburgh tap water," said Mr. Bell.

Yet, he'll also defend the need for a service that helps those without easy access to tap water, those who don't like the taste of tap water or perhaps are served by aging infrastructure.

A spokeswoman for Pittsburgh Mayor Luke Ravenstahl was recently quoted as saying the mayor would like to reduce the city's reliance on bottled water, which it buys from Atlanta-based Crystal Springs, but that old pipes in the City-County Building have a tendency to turn the tap water into something unpalatable.

Just how much impact the heightened publicity over bottled water issues has could be a little clearer in a couple of months. Summer is among the strongest selling seasons for bottled beverages, nationwide, and the team bottling Tyler Mountain Water admits to a fondness for hot spells like the one that's hit the region in recent days.

But they've got a strategy to help fill in business during the cool weather, too. A few years ago, the company added coffee services.