Mention Watergate and you get an instant response of recognition. Mention James F. Roberts and it is likely to be a "who-he" stare.

In real estate, Watergate means the luxury, highrise community of three cooperative apartment buildings, two office buildings, a hotel and a shopping mall in Foggy Bottom. Jim Roberts doesn't live there but he was project manager during the construction of the first building and an engineering consultant on later buildings.

Now Roberts is involved with the development of the $80 million, four-building Watergate at Landmark condominium in south Alexandria and the new $14 million Watergate of Alexandria development of traditional, luxury town houses in the Old Town area.

Since 1975, when Giuseppe Cecchi left the Watergate subsidiaries of Societe Generale Immobilaire and his Immobiliare U.S.A. operations to go his own way with International Developments, Inc., West Alexandria Properties, Inc., and Royal Developments, inc., for residential developments in this area. He also has a role in overseeing other Immobilaire U.S.A. developments in California.

Roberts is a 45-year-old native of Boston who grew up in tiny Gatesville, Tex. He began driving a truck at 16 and took up carpentry at 17. He served as a radarman in the Navy.

Later, he decided to head for Washington, where he was hired as a carpentry foreman by builder Victor Beauchamp.

"He was a fine man," Roberts recalled the other day. "He encouraged me and promoted me to superintendent of a job at Gallaudet College. Victor Beauchamp also urged me to get more education.

"I enrolled at George Washington University and went through a seven-year period when I was taking 110 hours of engineering and related courses five nights a week. I didn't get a degree but I got the technical knowledge that a general superintendent should have."

Since then, the Roberts dossier shows that he has been involved in general contracting, has been a project manager for both residential and commercial development projects and has done consulting work. From 1973 until he was tapped to be head of are Watergate developments, he was exclusive consultant to Immobilaire U.S.A. and Immobilaire Canada, Ltd., both subsidiairies of Societe Generale Immobilaire, the Rome-based international development conglomerate in which Vatican funds have been invested.

In the past three years, Robert has moved up to the top level as the main man for the big developer. He said he rises at 5a.m. and gets to his Alexandria office by 7a.m. " to get some work and thinking done before the phone starts ringing at 9."

Roberts and his wife and their four children, ages 8 to 18, live in Ozen Hill. He likes to do some cabinet and woodcrafting in his home workshop. And he also is a airplane pilot who has "a hard time getting in the air these days, just flapping my wings."

AS a generalist now in development, Roberts meets with financial and marketing people, as well as planners and condominium association specialists."But I still like walking the job," he says. "I like to get to both sites (Landmark and Alexandria) at least twice a week."

With the Landmark apartment project well under way and scheduled for completion in 1979 and the Alexandria town houses already in a revamped design stage, Roberts is looking for the next Watergate project.

"We're here to stay," he said. "But another highrise would not be as big as Landmark with its 1,500 units. And I don't know where it will be. But we like Washington and think that Washingtonians like what we've done."

In terms of marketing, Roberts defers to Lee Elsen, senior vice president who has been selling Watergate dwellings for about 15 years. Elsen and his wife recently moved from downtown Watergate to Landmark.

But there's no doubt today that Roberts is the boss of the Watergate residential projects! Immobiliare U.S.A. now also owns the Embassy Row Hotel on Massachusetts Avenue. "That operation is looking better," Roberts said. However, his parent group recently sold off the last of its interest (hotel, office building and shopping mall) in the orginal Watergate.

Roberts predicts that Watergate at Landmark will be a significant socio-economic complex of the future. He agrees with condominium association consultant David Wolfe that cando owner-residents participate in a "grass roots from of democracy."