First it was the faulty fire alarm. Then the fountain did not work. The garage still leaks and the tennis courts do not drain properly.

But the swimming pool, said Franklin Markwith, was the last straw.

Last month the Alexandria Health Department shut down the swimming pool at The Oympus, a 255-unit luxury condominium within splashing distance of I-395, near Landmark Shopping Center. The owners are steaming.

"We swam in the pool last summer," said Markwith. "We didn't think anything was wrong. But we now know those dark green spots in the corner were fungus."

The health department cited deficiencies in the pool's filter system that have gone uncorrected since the Olympus opened in 1975. Until the legal question of who should foot the estimated $25,000 repair bill is settled, Markwith and his "Condo Canyon" neighbors are in for a dry spell.

"We've been taken for a ride," said Markwith, a 62-year-old semiretired mechanical engineer who is to The Olympus what Howard Jarvis is to taxpayers.

Markwith is leading his co-owners, mostly senior citizens armed with petitions, polls and electric typewriters, in a revolt against The Olympus board of directors, who voted two weeks ago to split the cost of the repairs 50-50 with the developer.

Max Rush, president of the board for the past three years, refused comment. "I'm like Mr. Nixon," Rush said. "I don't give interviews for free."

Markwith feels the developer should pay the entire amount. "I'm trying to get legal advice." he said. "I don't feel the owners should pay for something twice, I've been a fighter all my life. We'll sue if we have to."

The Olympus is not the only condo-minimum with problems. Rumblings from other residents of "Condo Canyon," the stretch of more than a dozen high-rise buildings lining both sides of Shirley Highway, prompted one owner-resident to refer to the growing rash of complaints as "Condo-Gate."

"It's the same old story," said Virginia Real Estate Commission investigator William Stimson. "The developers go in, sell the units and leave the owners with all the problems."

At Alexandria's Parkfairfax there are "a myriad of things" that have upset purchasers, said Wayne Brown, another investigator with the Virginia Real Estate Commission. "They tried to renovate the building without vacating some of the residents. There was a lot of dust, dirt, strangers in the halls, workmen leaving doors unlocked, thefts and just general inconvenience."

At The Representative in Arlington there have been complaints of paints chipping off the building's tan exterior, at Watergate at Landmark, noise problems; at the Lifestyle Condominium in Herndon, drainage problems in driveways, Brown said.

"The noise is so bad I can't sleep at night," groused one penthouse resident of an Alexandria condominium near Shirley Highway.

Some of the canyon's high-rise monuments to modern living - concrete and glass balconied beauties, whose luxurious amenities and slick sales brochures promised peace and privacy to thousands of buyers in the early 1970s - are turning into hotbeds of dissent.

"Alexandria wasn't prepared for the problems associated with condos," said one angry owners. "The Olympus is a good example."

Advertisements for The Olympus spoke of life there as "just you and your neighbors around the pool. . ."

But co-owner John Meisburg, cooling his heels in the 92-degree heat, now say he's "pretty darn mad" about that locked-up facility. "The pool was the main reason I moved here."

Privacy, said other owners, was another reason. Markwith is doing something about that, too.

A slightly balding, bespectacled man with a persuasive manner, Markwith is leading the condo cave-dwellers into the fray: buttonholing co-owners in the elevator, taking opinion polls, holding meetings in his shag-carpeted living room and spending hours on the phone. "Some people think I'm nuts," he said.

The investigation into the swimming pool began a few months ago, when Markwith (as a member of the board) was informed of the deficiencies. He fired off letters to the trustee (First Virginia Mortgage and Real Estate Trust, which took over from the original investors in 1975) and waded through the health department's files. During the first week in June, Markwith filed a formal grievance with the Virginia Real Estate Commission in Richmond.

He was not alone. A spokesman for the commission said recently that complaints from condo owners in the Northern Virginia area are more than they can handle.

"We've gotten formal complaints from 11 condominiums since January," said chief investigator Stimson. "In my opinion, that's an excessive number. Ninety percent are complaints of misrepresentation - people promised things they never got. We do not have the personnel to handle the investigations.

Markwith reels off a list of what he says went wrong with The Olympus: the leaking garage, the dried-up fountain (which Markwith tried to fix), the rainwater that does not drain off the tennis courts. Last year, Markwith said, the fire alarm system was found to be inadequate. An occupancy permit had been issued, he said, a few months before by the fire chief. The trustee agreed to split the cost of repairs 50-50 with the owners.

"I'm afraid that set a precedent," Markwith said, shaking his head and leafing through a stack of papers. "Now we come to the pool, which is the most serious."

Markwith maintains that the trustees knew all along that the pool did not meet health department standards, but tried to delay repairs until after the building was turned over to the owners on Jan. 1, 1977.

William Corish, president of First Virginia, said the trust's responsibility as property developer ended last year. "It's impossible to make 210 people happy," Corish said. "We've already spent a lot of money at The Olympus, and we don't feel we should have to pay for the pool."

Health department records show that the pool, from the time the original plans were submitted in 1975, had an inadequate system for recirculating water, which must be fresh every six hours. The pool's filter room was also flooding.

Charles Higginbotham, who inspected the pool, said the health department allowed the pool to open in 1976 and 1977 - knowing of the potential health hazzard - because the building was only partially filled and there were only a handful of swimmers.

Files also document that Shannon & Luchs, the trustees' selling agents, were notified of the necessary repairs, which were never made.

William Everngam, Shannon & Luchs' property manager for The Olympus at the time, declined comment.

A new pump was installed in the fall of 1977 at the developer's expense, but the health department says it did not correct the problem.

This year, on May 16, the pool was not allowed to open, an action which took many co-owners by surprise.

Markwith said the only thing owners noticed last summer was a life guard sprinkling chemicals into the water. Higginbotham said the hand-sprinkling of chlorine, a result of the filter system's poor circulation, is not allowed by city regulations. "It wasn't a serious health hazard," said the official," but I wouldn't have let my children swim in it."

In retrospect, the health department official says, they were too nice. "We learned how these developers operate," he said. "They promised and promised to fix the pool."

Corish would not comment further, except to say that First Virginia has agreed to pay for an engineering study to determine the extent of the repair work.