Carbonated and noncarbonated bottled water also were judged.
Final results weren't available at press time.
Atlantic City, N.J. - winner in three of the last six contests - was eliminated in an early round, a contest official said. Berkeley Springs, Hancock and Hagerstown were also eliminated early, the judge said.
The taste of municipal waters, or tap waters, are usually easier to distinguish than bottled waters, said Arthur von Wiesenberger, the 1997 Water Master. Before the water-tasting got under way, von Wiesenberger led a seminar for judges to help them know how to do the job.
But even bottled water can awaken the taste buds.
Judge Eve Zibart picked up quickly on the distinguishing characteristics of two carbonated bottled waters during a mock tasting before the competition began.
One of the waters had a limestone taste, while the other tasted as if the bottle had a metal cap, said Zibart, who writes a weekly restaurant column for The Washington Post. She was right on both counts.
For others, it wasn't as easy to judge the flavor of different waters.
"Water is very tricky and hard to taste," von Wiesenberger told the judges as he prepped them on how to rate water by flavor, odor, appearance, aftertaste and how it feels in their mouths.
"It's hard. You have to really concentrate on the nuances," said judge Kathie Gartrell, who works for the National Geographic Traveler.
Waters are as unique as fingerprints, said von Wiesenberger, a food critic for an ABC-TV affiliate in Santa Barbara, Calif.
Water should be crystal clear with no odor and no taste, he said.
To judge the water's flavor it should be swished around the mouth to reach all of the tongue's taste buds, von Wiesenberger said.
Water treated with a lot of chlorine tastes like pool water, he said, adding that water treated with little chlorine might taste like algae.
The judges were advised not to make noises when tasting the waters and not to talk to each other during the competition.
To keep their taste buds uncluttered the judges were scheduled to eat a meal of white rice. In between sampling waters they could eat thin, bland water crackers to get rid of any lingering tastes.