A couple of years ago, Perrier water's tingly natural bubbles bounced on the tongues of only a few American bon vivants wealthy enough to pay $1 for that summer-green, bowling-pin shaped bottle.

But sales have mushroomed -- from 2 1/2 million to 100 million bottles lase year -- and Perrier hopes those figures will triple in 1979. A $75-million plant is being built here exclusively to supply an American marked, and operations begin this month.

"We have moved as much as 300-500 cases in a two-day period at our Wisconsin Avenue store alone," said president Leonard Rodman at Washington's Rodman Discount Drugs, Inc.

Schweppes USA Ltd., a subsidiary of the English Schweppes, recently became the first soft drink company to put out a competitor -- a processed water with artificial carbonation called "Schweppervescence.

But no competitor has the snob sppeal of being bottled in prestigious Southern France. And Perrier alone has blitzed the tube with Orson Welles proclaiming in gravelly voice the "miracle" of Perrier. Welles' gushes, in precise actor's diction, rival the chorus of gases and gurgles in the background: "In the South of France, near the village of Vergeze stand gates which guard a single spring... blessed with waters of unusual purity and clarity..."

So to see what all the furor was, we came to the Source in this tiny township to view "the single spring" where the Perrier folks say the water "has been bubling up from an underground volcanic spring at the rate of 21,000 gallons per hour for nearly 2,000 years."

The one-hour flight from Apris to Montpelier, the nearest airfield, was taken with Fred Zimmer, the enthusiastic board chairman of Perrier's U.S. subsidiary, Great Waters of France, Inc. At 20,000 feet, the Dutchman admitted that Perrier's statement that the water "is bottled directly from nature" is not quite literally the case.

The water does indeed bubble up from deep below the ground surface, but in order to control the consistency of the carbon dioxide, the gas and water are separated, brought up from the earth in different popes at separpate points, then the gasses are reinjected in the bottling plant.

"fifteen, 20 years ago, sometimes there was not enough gas, sometimes too much. We take part of the gas from one place, separate water from the gas and put them back together in the same bottle. "It is all naturally carbonated water, but you have to be very careful with the spring," Zimmer explained.

Greeting the visitor after a 22-mile drive from Montpelier to Vergeze was the debris of construction. Puffs of dust blanketed the low white administraion buildings and laboratories. Workers labored around the clock to meet the planned opening date of the new factory. After the opening Perrier will employ 2,000 people in Vergeze.

The visitor was not taken directly to the spring, but to the plant to see the bottling of the water. The sand from their own mines goes in one side of the plant to make bottles that bake at 1600 degress and fly down red hot from furnaces. The water is piped into bottles, capped, labeled and emerges on the plant's other end.

But where is the spring, rising "throught porous limestone and cracked marls?"

The spring must await a visit to the laboratory where, with an array of sophisticated equipment, George Perras, quality and product control supervisor, oversees a staff that twice daily performs chemical analysis on the spring and bottled water.

"We have never found any bacteria, or any variation or any pesticides," he said. "One old man who had worked here many years had only one regret at retirement: He had neve found any bacteria."

Why is the gas taken out and put back in the water?

"if we transport water and gas together in the same pipe, it will not work. We've been doing it this way for 36 or 37 years."

Then finally, the Source.

The four officials marched a visitor to their Peugeot for a brief ride to the site. An imposing mansion on beautifully landscaped grounds, it was the home of Sir St. John Harmsworth, who purchased the spring in 1903 with the money he made from selling his stock in the family business -- the London Daily Mail. The parade continued up a terraced walk to... a white gazebo. Inside the gazebo was a protruding pipe.

"This is the Source," said Louis Foursans, somber in a gray suit. He is in charge of the entire Perrier operation except bottling. There was a pixie-ish expression on his middle-aged face.

"There is no spill. We don't want that because of possible bacteria," he explained.

Fifty yards away, beneath a bird-bath-sized fountain convered by a Plexiglas half sphere, fizzed lightly mineralized water with pure natural caubonation. This place, Les Bouillens, as the local villagers call the spring, is the only view of gurgling waters.

The Plexiglas top had been removed only once in recent years -- for thd Orson Welles commercial.

Mas Pelera, the point where the carbon dioxide is removed, is across the way, surrounded by a white picket fence.

"Now, you have seen all our secrets," said Zimmer, adding, "in Perrier, nothing is added, nothing is dropped, nothing treated. We can withstand investigation, so if anyone wants to investigate what we do... we've not worried."

When Gustave Leven, chairman of Sourve Perrier, began looking at the American market a few years ago, most market reps weren't interested. But the 63-year-old Frenchaman persisted and two years ago hired marketing whiz Bruce Nevins (who put Levis on the international map) to head his operation.

Nevins has tried to convince American supermarket shoppers that it is better to reach for Perrier than Pepsi or Coke. He hired salesmen from the soft drink industry, tripled the million-dollar advertising budget, lowered the price of a 23-ounce bottle to an average 69 cents, and emphasized the drink's health properties.

By 1981, the French hope to capture 1 percent of the soft drink market.

But the American soft drink people remain unconvinced that the "natural craze" will drive Americans to forsake pepsi for Perrier. One executive doubted whether "the American palate is trained" to carbonated spring water.

Thought Perrier's natural carbonation puts it in a special class, bottled water of all kinds is big business today. Aficionados rank imported still waters like French Evian, Itailian Fiuggi and Belgian Spa quite high. One blind tasting of sparkling waters conducted by Savor magazine placed Perrier third, after a little known Swedish water called Ramiosa and the German Apollinaris.

This country's healthomania has driven the number of American bottlers up to 700, but 70 percent of the water sold in this country is actually tap water that has been treated to remove bacteria, pollutants and traces of harmful metals, according to Fred Jones, director of the American Bottled Water Association.

Officials here are fond of saying that since 218 B.C.when Hannibal rested his troops in this small township, the water has slaked the thirsts, treated the ills and lifted the spirits of over 85 generations.

Emperor Napoleon III supposedly ordered that the spring waters be bottled "for the good of France" in 1863 and the French government has kept close watch on the spring ever since. The government makes surprise visits to the plants to assure quallity control tight standards.

Contrary to American notions that Perrier is a household word in France, a still water called Contrext Ville (also owned by Perrier) is the biggest seller in France. Perrier is second.

When does the Source run dry, Zimmer was asked. "The Source can't run dry, oh, perhaps with 10 billion or 20 billion bottles we, should have some problems. But the well is so big... we don't even know how big." Gallic overstatement? Perhaps. But one thing is certain. The Pfrench are still cashing in on the cachet.