The three judges, dressed in clinical white coats, raised their glasses to the sun. They smelled the liquid, sipped it and swished it around in their mouths.

Tap water.

Not even Perrier. Not a twist of lemon in sight.

Washington, D.C., was one of seven challengers pitted against New Orleans, last year's drinking water champion, in a blind taste test of tap water sponsored by the American Water Works Association. The other competitors in the second annual contest were Boston, Atlanta, Honolulu, St. Paul, Ottawa and Olympia, Wash.

Photographers, reporters and registrants in the American Water Works Association's annual conference huddled together in the sunlit courtyard of the Sheraton Washington Hotel yesterday to watch the judges deliberate before eight numbered flasks on a blue cloth-draped platform.

The judges, "an international panel," consisted of French water research specialist Franc,ois Fiessinger; Ronald F. Packham, from a British water industry research laboratory, and Nina McClelland, head of the National Sanitation Foundation in Ann Arbor, Mich.

There was an immediate snag. No. 5 was too cold.

"I'm putting it aside," muttered McClelland to Packham. "If it warms up, I'll try it again."

"It doesn't stimulate the taste buds the way a room-temperature glass of water does," explained AWWA information director Bob Spangler over the PA system.

The judges then tested the waters for the official criteria of "clarity" (suspended matter in your water is a no-no), "aroma" (a fishy smell just won't do), "feel" (soapy or astringent?) and "flavor" (a chlorine, metallic or other pronounced taste was frowned on).

The judges' palates went to work.

"I trust you're arriving at the conclusion that these judges are serious," Spangler announced to the crowd. "It's serious business and they're not fooling around."

"Two and Eight are out," said Packham.

Six was the next to go.

"Let's do Five again -- it's warmed up a bit," said Packham. Fiessinger cupped his cold No. 5 in both hands. "It's like warming up cognac," he said with a smile.

Four and One were the next rejects and, in less than a hour, three winners were selected. William Richardson, president of the Denver-based AWWA, strode up to the podium to announce them. And Washington, D.C., tap water drinkers, was not among them.

In first place was Olympia, Wash., followed by Boston and Honolulu, which turned out to be the troublesome No. 5 (the chilling may have contributed to Honolulu's lower rating, said Richardson).

"I'm not surprised, but I'm excited," said Len Esteb, Olympia's deputy director of public works, as he stepped on stage to accept the silver goblet.

"It had no objectionable aroma at all," said Packham afterward about the winning water. "Just a touch of chlorine, fresh to the palate. Very clear -- an absence of color or suspended material. It was beautiful drinking water."

Although there was a "wide range" of quality among the entries, said McClelland, "if you were to drink any of the water you wouldn't find it unpalatable."

Water tasting, said Fiessinger, "is not a question only of training; it's a question of ability. Some people do not have ability . . . You need not to smoke."

When asked to compare his wine tasting with his water sampling, Fiessinger said, "The approach is the same, but the criteria are different."

And there you have it.

"It's a promotion," said Spangler about the blind-test idea he conceived. "But it's a promotion for a product that people take for granted, and they shouldn't.

"It really is the single most important manufactured product in the world. You've got to have water."