THE WATER BAR, 1701 20th Street NW.

A Friday night near Dupont Circle. The bartender's seeing to it that the glasses are full and the ashtrays empty and no one's getting too loaded. The Eagles and Elvis Costello clamor in the background. Along the bar and at the tables couples are talking and singles are stalking.

But wait a minute. The lights are awfully bright. The walls are azure blue with white bubbles; the bar snack is Pepperidge Farm goldfish, and someone's discussing the merits of Badoit versus Evian. French wines? No, French waters; nearly everyone in the place is drinking H2O.

This is not a case of post-New Year's Eve delirium tremens. It is the Water Bar, downstairs at the Golden Booeymonger, a new Washington nightlife option.

Last summer Ronny Vogel, one of the three young owners of the Booeymonger restaruants, was basking on the beach at Rehoboth, listening to the waves and reading "The Book of Waters."

It described the variety of bottled waters available, their origins and growing popularity in the U.S. In the hot sun his thirst grew into the idea of opening a water bar in Washington. By November the staff was pouring out 11 carbonated and 4 noncarbonated brands like, well, water.

"We've never had to throw anyone out because they were too drunk," jokes the bartender, "but one night, a guy got so bloated we had to carry him out."

After trying free samples, customers may buy by the bottle, case or six-pack. The carte des eaux gives brief descriptions, some of which sound like warnings. Although Vichy water has a "volcanic tang" that "takes getting used to," it is "one of the world's most popular waters." Poland Spring has been the favorite of such as Alice Cooper, Calvin Coolidge and Mae West.

On request the bartender will guide one through a tasting, telling where each spring is located, the mineral content of the waters and their alleged healing powers.

Some patrons say they're drinking less now, have stopped smoking or started jogging or have switched to water because they've passed the dreaded threshhold of 30. Others say that after a weekend of hard drinking, they still want to get out and socialize but not to indulge in alcohol. Others mention how Europeans have been drinking bottled water for years.

"It's a combination of snob appeal, concern for proper nutrition and the fact that bottled water really does taste good and is more refreshing than tap water," Vogel explains when asked why people will pay as much as $1.92 for a glass of water. They buy bottled New York City tap water in Beverly Hills, so why shouldn't European sulfur solutions sell in Washington?

The kind of chat you hear in a water bar:

"Let me try some of that famour stuff, that Perrier, you know?," a young bearded man in a leather vest and blue jeans says.

"My favorite sparkling water is Saratoga; that's the house water here," a blonde in a white cocktail suit tells a friend.

"I'm trying to perfect a THC liqueur," the guy in the cowboy shirt confides.

"Where's the men's room?" several ask.

If there is water, water everywhere, not everyone is drinking it. Those women at the corner table are having wine spritzers, the long-haired fellow at the end of the bar is drinking Remy and another man just ordered a White Russian. Bloody Marys, beer and Jamaican rum are going down.

"The other night two girls came in and sampled all the waters wth bourbon," the bartender said.

The Water Bar stocks a full supply of the hard stuff, serves light meals, and in many ways is like any other bar.On water alone, the business probably wouldn't survive right now, but with the energy-starved '80s here, all the alcohol may have to become gasahol, and Vogel could find himself pouring the crest of a new wave.