While interest in retirement communities is apparently growing -- as the population of older Americans burgeons -- the high cost of building those communities and a lack of large parcels of land close to metropolitan areas is limiting their development.

While two such communities are planned for this region, one in Frederick, Md., and the other at Annapolis, the federal government and private developers here and elsewhere are turning to smaller projects or high-rise condominium development as a cheaper alternative to new communities. The adult projects are limited to residents age 50 and above and, like the larger communities, stress convenience, social activities and a quiet atmosphere away from children. They also offer security and medical facilities.

Dozens of new adult developments have been built in recent years, particularly in Florida.

Some existing adult communities, such as Rossmoor Leisure World near Olney, are in country club settings and cater to the more affluent. Others are geared toward retired people on low, fixed incomes -- the constituency some housing industry specialists say is more important to the quickly growing elderly community.

Some people in the housing industry point out that many of the communities are isolated in out-of-the-way areas; some residents complain that they are living in old-age ghettos, cut off from younger people.

"I don't like homogeneous communities," said Fran Robbins, 57, as she munched fruit salad in one of Rossmoor's numerous activity rooms. "But there's no other place I can live and have what I have," meaning a house she does not have to maintain herself.

While Robbins, a Rossmoor resident for two years, said she enjoys the activities, security and her home, "I would not have chosen this if there was some other place. I think it's nice to have young people and old people in the same place. I like to see pregnant ladies and little kids running in saying, 'Hi,' people selling Girl Scout cookies."

Retired State Department official Luther J. Reid, working in the Rossmoor wood shop, said Rossmoor was a "nice, convenient" place to live but added that the lack of younger people "is the biggest vacuum out here." Reid suggested that "one right, quick court case" might elimiate the zoning for the area for those over 50.

Crestwood of Frederick, Md., an adult community being built by the New Jersey-based Crestwood Villages Inc., is scheduled for opening in April, and is also lower priced than Rossmoor, according to a spokesman for Crestwood's advertising agency. The community is for those active retired and semiretired aged 52 and up, the spokesman said.

The prices will range from the low $30,000s to high $60,000s for one-level, two-bedroom detached homes, condominiums and two-story homes, the spokesman said. The community will also have a recreation facility, swimming pool, tennis courts, sauna and other recreational amenities. It is patterned after the 13-year-old Crestwood Village of Whiting, N.J., which has 10,000 residents living in a 1,000-acre parcel of land, the spokesman said.

Another adult community, Heritage Harbor of Annapolis, is scheduled to begin showing models next month, according to Robert Sithens, vice president for administration of the Washington division of U.S. Home, the project's builder. The community, on Heritage Harbor peninsula just below Rte. 50 in Annapolis, will consist of 1,400 mostly detached homes for persons 45 years and older with children 18 years and older, Sithens said.

The development, which Sithens said will take about 10 years to complete, will include such amenities as community building, indoor and outdoor swimming pools, an auditorium, a restaurant, billiard room, sauna, exercise room, and a closed circuit television studio for residents. The two and three-bedroom homes will cost between the high $60,000s to about $90,000, Sithens said.

The maintenance fee for the project, including cable television, will be about $65 a month, Sithens said.

"Twenty years ago nobody ever heard of an adult community, where old people wanted to be separated from younger people," with amenities such as a clubhouse, 18-hole golf course, swimming pool, lawn-bowling greens and 24-hour security guards and numerous art crafts and classes including belly dancing, said Marika Sumichrast, vice president of marketing and sales at Rossmoor.

'We don't have to fall over tricycles and slip on roller skates," said Rossmoor resident Homer Ulrich, 72.

Developer Ross Cortese is credited with starting the adult community concept in 1957 when he developed the first Leisure World, in Seal Beach, Calif. He has since built seven other such communities.

Sumichrast said the Seal Beach Leisure World has a waiting list for its units, which sell for $30,000 to $44,000. Houses and apartments in Rossmoor in Maryland cost between $66,500 to $106,000 with additional monthly maintenance fees of $192 to $225. The fees also cover, utilities, the club house, swimming pool and the 24-hour guard.

Reid, who lives in one of Rossmoor's cooperatives, said his monthly mortgage payment, including maintenance, is about $450 a month. "I think it's very cheap out here," Reid said. "My monthly outlay would be 30 to 50 percent grater" elsewhere in the Washington area, he said.

Many of the nation's elderly can't afford to live in a Leisure World, however.

Floyd Hyde, a former under secretary of the Department of Housing and Urban Development, says that retirement communities are fine for some, but there aren't many elderly wealthy enough to pay Rossmoor's high prices. Hyde told the House Select Committee on Aging earlier this month that proposed cutbacks in federal funding would reduce by 6,000 the number of units available on the rental and sales markets in 1980 for the elderly. Hyde said that by the year 2000, 30.6 million people will be age 65 or over -- a 35 per cent increase over the current population. Four years ago four-fifths of all older persons living alone or with unrelated people had annual incomes under $6,000, while less than half of the non-elderly population is in that income category, he said.

Hyde added that more than 50 per cent of the elderly live in housing built before World War II. Housing is the largest expenditure for these people, with people over 75 paying up to 48 percent of their income for housing, he said.

Those who have houses cannot afford the upkeep and maintenance, Hyde said.