The Olympic-size swimming pool is "real neat," according to 5-year-old Stephen Hritz. Executive Don Anderson says the squash courts are "out of this world," and ballerina Lisa deChaby calls the dance studio second only to the rehearsal area at the Metropolitan Opera.

The pool, courts and dance studio are all part of Fairfax County's "Supercenter," the $2.7 million Wakefield Recreation Center and park complex in Annandale.

Since the facility opened in April last year, an increasing number of fitness fans have discovered the Supercenter's charms. From an attendance of about 500 a day in the first few months of operation, Wakefield now attracts an average of 1,000 people daily.

In the wake of the center's success, the Fairfax County Park Authority has scheduled construction of a second Supercenter at Lee District Park to begin at the end of the year, with completion planned for the summer of 1980. The new $2.5 million center will be modeled after Wakefield, offering something for everyone.

"We've got a pretty good range of activities here, so people can come and exercise as they see fit," said Wakefield's general manager George Sachs. He gestured toward the 100-by-90-foot multipurpose gym where two basktetball games were in full swing, a blond teen-ager twirled a baton in one corner and an intense younster practiced a karate routine in another.

The center's main attractions are the 50-meter indoor swinning pool, which holds 500,000 gallons of water and up to 500 people, and the multi-use gymnasium, Sachs said.

The building also houses four handball and two squash courts, a fully equipped exercise and weight room and a dance studio with mirrors and a ballet bar. There is a craft room with potter's wheels and a darkroom, a game room with table tennis and coin-operated video games, a pre-school classroom, a catering kitchen, two club rooms and a sports equipment rental and sales office.

Outdoors on the 280 acres of wooded park around the building are six tennis courts, four baseball diamonds, a jogging and biking trail, two football and soccer fields, 10 horseshoe pits, 16 shuffleboard courts, three multi-use courts, chess and checkers tables, picnicking facilities and playgrounds.

Plans are being made for construction of an outdoor amphitheater, five more tennis courts, including a tournament court, archery and field games and a winter sports area for sledding, skiing and skating.

With all of these recreation possibilities wrapped up into one center, it's no surprise to find that Wakefield attracts regulars from as far away as Rockville and Landover, Md.

"In the summer you'll see license plates from Louisiana, Florida and New York in the parking lot," Sachs said. "When relatives visit, people like to bring their families here to recreate and to show off the facility."

But the majority of those using the center are Fairfax County residents, said James Heberlein, assistant director of park operation for the Fairfax County Park Authority.

County residents account for 78 percent of the pool use, 64 percent of the gym use, 80 percent of the dance studio use, 93 percent of the classroom use and 69 percent of the weight room use, according to Park Authority studies.

"Like all revenue-producing park facilities in the Fairfax County park system, the building gets no tax money at all and is self-sufficient," said Heberlein, who noted that tax dollars aere used only in developing the building.

Because federal funds were used in procuring the land, the park service must make Wakefield available to non-county residents, but may charge preferred rates for users from Fairfax County, he said.

General admission is $1.50 for an adult and $1 for a child, with additional fees for handball and squash court time, dance studio and club room use. County residents may purchase passes good for 25 admittances at a cost of $30 for an adult, $20 for a child and $15 for a senior citizen. These fees adequately cover Wakefield's costs, Heberlein said.

Manager Sachs noted that the new Lee District recreation center should benefit from Wakefield's minor design mistakes. Design suggestions offered to Lee District planners include providing tighter security at the admission areas and building more racketball courts.

Open from 5 a.m. until 11 p.m. everyday except Christmas, Wakefield attracts early morning handball players and weight lifters as well as the daytime pool crowd and nighttime basketball enthusiasts.

"We come, and we stay," said Linda Huther, of Annandale, who brings her two children and their friends to the center at 11 a.m. and leaves around 5 p.m. four times a week. "I think it's just magnificent. We eat lunch upstairs at the snack bar, the kids swim, and they've met new friends outside of the neighborhood."

"It's a great facility and there are no hassles, other than it's being so far out," said 28-year-old Chauncey Anderson, of the District, who drives two or three times a week to use the gym. "In D.C. they don't have a facility like this except the 17th Street 'Y,' and that's ridiculously expensive."

Wakefield is "tremendous," according to Tommy Coker, a minister of music from Falls Church who brought his children to swim on a recent morning. "We really can't afford, and it's not worth belonging to a private club, so there is real need for something like this where the children can learn to swim."

"It was the answer to our prayers," said dancer deChaby, of McLean, rehearsing in leotards, tights and toe shoes with dancer Jill Becker, of Arlington. "We were wandering around looking for a place to practice where we didn't have to affiliate with any studio. Here we can rehearse together with the hope of building a little company just for the county."

"I come here because it's the closest public squash court I know of," said Peter Bruce, a Department of Transportation employee who uses Wakefield's courts on his lunch hour.

"There isn't any place like it for miles around," said McLean resident William Pearson who, with hie wife Karen and children Christopher and Timothy, splashed around the shallow end of the pool. "I wish they had a kiddied pool, though."

"I think it's excellent, because they regulate it so you can swim laps no matter how crowded the pool is," said a soggy Fairfax woman as she dashed off to sauna. "It's a fabulous place."