Washington mega-builder Sam Pardoe had the plumber, the trash hauler, the electrician, the landscaper and even the kitchen sink installer over for a genteel Georgetown housewarming last night. Pretty soon, it turned into a downright respectable disco party.

Strobe lights. Linda Ronstadt. The Village People. "YMCA" blaring from 50 speakers. Three hundred guests. A dance floor looking out onto a terrace, lighted trees, a Roman bath. And a spouting fountain.

It was not your typical Friday night on Q Street.

"This house has been a dream of mine since the day I started building 15 years ago," said Pardoe. "It's taken that long to get the damn money to do it."

That amounts to $400,000 in 2 1/2 years to get Pardoe's new house from ground-breaking to party-giving stage.

So last night, this man who has built about 70 of the area's grandest homes -- some of them with 12-foot ceilings and nine bathrooms -- had a party for those who helped build the latest.

"That's the first time I've put Christmas lights on an elevator," said Archie Burgess, who did just that. Burgess, like just about every other contractor who came, stood around admiring his work.

His wife, however, admired the brass fire pole that stretched from the first to the fourth floor.

"Am I going to slide down it?" she asked. "Not with those lights on it, I'm not."

Then there was Bob Burnett who sold Pardoe the automatic machine that opened and closed the door to one of the bars that seemed to pop up everywhere.

"Come over here and look at this," he cried. He flipped a switch, watched the door close smoothly and silently, then grinned like a Cheshire cat. "Absolutely beautiful," he said.

At least one person wasn't admiring his handiwork last night. That was Nestor Caryk, 18, the gym installer. He chewed bubblegum, stood on the sidelines and admired the female guests.

"A lot of nines," he said, explaining his rating system of one of 10. "At the parties I normally go to, there are girls. These are women."

Going to the bathroom at the party was difficult, since everybody crammed in to admire the wall-to-wall glass and exotic amenities. The gold push-button toilet paper dispensers popped out of the walls, and each bathroom had a push-button phone. "Very convenient," said Jean Altimont, spying the phone near another toilet in another bathroom. Her husband did all the marblework in the house.

Among the other domestic marvels were: an electric train that ran along a track mounted on the walls of the library; a Jacuzzi; a well-stocked wine cellar; ceiling fans; Oriental rugs and rooms that opened onto indoor balconies full of plants.

The party had a stiff beginning, since landscapers tend to congregate with landscapers and carpenters with carpenters.

But then somebody got the idea to turn the music up loud enough so nobody could talk. Everybody was either forced to dance or stand around stupidly and watch the others dance.

So Bob Thompson, the elevator contractor, grabbed Lorraine Tuthill. "We'll put these kids to shame," said Thompson as he whipped her around the dance floor.

Upstairs, people were eating. Really eating. Like legs of ham and roast beef and crab puffs and cheese and quiche and fruit. Everywhere you looked was food.

"Catered and everything," marvelled George Lemley, who installed the tile in the utility room. "Best party I've ever been to."