While its family population stagnates, the Washington area is experiencing an upsurge of households consisting only of adults, a shift in living patterns that has sharply altered the once child-dominated suburbs and contributed powerfully to the revitalization of the city.

From 1970 to 1977, the number of families in the area with children under 18 rose by 4,500 -- an increase of just 1 percent, according to a new report by the Greater Washington Research Center.

Meanwhile, the number of adult households without children -- singles, childless couples, upwardly-mobile young adults, or "empty-nester" elderly whose children have grown up and left -- rose by 149,000, or 31 percent, the report said.

These all-adult households now make up slightly more than half of the households of the suburbs and almost three-quarters of those in the city.

In contrast to the baby boom decades following World War II, change in the area now "is oriented not toward the needs of children but toward definitely adult interests and living patterns," said Eunice and George Grier, the demographers who wrote the new report.

"The lifestyles (of these new adult households) differ substantially from those of the typical family with children," the Griers continued, "and they are likely to have different attitudes toward a number of questions -- such as . . . school bond referendums and the advantages and disadvantages of living in cities."

Among signs of the shift, George Grier suggested, are school closings, the spread of all-adult apartment complexes that exclude children, the conservative turn in suburban politics, and the spread of city-type high-density development to parts of Alexandria and Arlington County which used to be "family suburbs."

These adult households predominate among what the Griers call the "new urbanites" -- the "accelerating influx of young, upwardly-mobile adults . . . (who are) supplanting shabbiness with chic" in Capitol Hill, Mount Pleasant, and a ring of other neighborhoods surrounding downtown.

In 1977, according to the Griers' analysis of new U.S. Census data, about 80 percent of the 16,500 new households moving into Washington had only one or two persons.

About two-thirds of them had household heads under age 35; two-thirds were white; and 89 percent moved into rental housing, although the Griers said that after a few years some may buy houses or condominiums in the District.

Even though they were well educated, their incomes were generally modest -- about the same as the $13,100 median for all D.C. households. About 45 percent of the new households came from the Washington suburbs.

As a result of these newcomers, the District's white population -- which had fallen by the mid-1970s to only about a quarter of the citywide total -- now is rising again, according to city government estimates.

Even during the 1960s, when the District's white population was plummeting, slightly more whites than blacks moved into the city. But according to Census Bureau tabulations, far more whites left. Many of those leaving were in their late 20s and early 30s, and apparently were establishing families and putting children in school.

"As long as (the) principal focus was on child-raising," the Griers said in their report, "most households wanted to be in the suburbs. They sought open play space and good (or at least new) schools. . . .

"But now, when all or most of the members of the typical household are adults, and all the adults are usually employed, schools no longer are a matter of primary concern. Play space assumes a very different meaning . . . (and) commuting takes on a newly negative value."

The one group of households now moving in large numbers from the city to the suburbs are middle-income black families with children.

In a report last month, the Griers suggested that these blacks are attracted to the suburbs for the same reasons as the whites who moved before them. Their movement was delayed, however, until their incomes rose and housing discrimination in the suburbs declined.

Most of the area's poorer blacks are remaining in the city, the Griers said, and apparently are moving to relatively low-cost, low-quality housing in the Northeast and Southeast sections, several miles from downtown.

Throughout the area, the Griers said, childless households now number 634,900, and comprise about 60 percent of the area's slightly more than 1 million households.

Although young adults under 35 are an important part of this group, they are substantially outnumbered by those over 45.

Almost half of the adults living alone have passed their 45th birthday. Among childless couples, almost 60 percent are over age 45-usually "empty nesters." There are now 112,000 such couples in the area, the report said, mostly in the suburbs.

Grier said their presence has contributed to a conservative shift in suburban politics.

"One of the main things people call on government for at the local level is schools," he said. "When their children aren't around any more, they figure they don't have much need for government, and they think it's costing them too much in taxes."

Overall, there are 180,000 households in the area -- singles or couples, married or unmarried -- that are under age 35 and do not have children.

"How luxuriously these young people can 'swing' depends at least partly on their incomes," the Griers said. "The statistics indicate that only a small minority are in the Porsche class," although their "discretionary income" is relatively great because they do not have to provide basic shelter, food, and clothing for children.

Of the single adults under 35 living alone, only 37 percent earned $15,000 or more in 1977. Among unmarrieds with a head of household under 35 and two more members, about 50 percent were in the $15,000-plus category.

Grier said there were no statistics available on how many of these households were couples living together, homosexuals, or heterosexual roommates.

All of the statistics in the new report are derived from a survey of 15,000 housing units in the Washington area conducted by the Census Bureau in 1977 and early 1978.