In a couple of weeks, about five years ahead of schedule, the mentally retarded residents of the Northern Virginia Training Center will be splashing around in a new $106,600 indoor swimming pool.

The pool - which the state placed at the bottom of its priority list two years ago - was privately financed by bake sales, candy sales, benefit dances and a country club luncheon. It was at last affair that doners who wrote out a check for at least $1,000 got their names inscribed on an honor roll of distinguished Virginians."

"I really sold it to them," said Jack Webb, a former member of the Virginia House of Delegates who now lives in Aspen, Colo, but maintains a law practice in Annandale.

The distinguished Virginian honor roll, which raised $100,000. was Webb's idea.Zoning lawyer John T. Hazel Jr. guaranteed a good turnout at the July luncheon by getting Gov. Mills E. Godwin to deliver the keynote address.

The parents associates of the training center began their drive last February with 67 cents. Early neighborhood charity efforts led fund raisers to believe that it would take five years to raise, enough money to build the pool. But that was before the luncheon for the distinguished Virginians.

At a dedication ceremony yesterday, center director David Lawson and other pool supporters saipped a red ribbon across the doorway to the facility, which will make possible additional therapy as well as recreation for the residents of the center.

Under the current water restrictions in Fairfax, imposed because the county's reservoir is at only one third of its normal level, pools can't be refilled, but the center got a special exception from the county. As Lawson explained, the concrete would not have cured properly and would have cracked if the pool were not filled with water.

John F. Herrity. chairman of the Fairfax County Board of Supervisors and honorary chairman of the pool committee told the dedication audience.

"The community itself, rather than some agency of the government, did it. And by doing it ourselves, we gained a spirit of unity that we wouldn't otherwise have."