Many of Washington's poorest blacks and Latinos are being forced into a tenuous, nomadic existence by the new wave of rehabilitation of rundown neighborhoods, according to an authoritative survey released yesterday.

Unemployment among the 300 randomly selected households surveyed in six rundown and transitional neighborhoods was "an extremely high" 24 percent, according to the survey by the Washington Urban League. Thirty percent of those questioned said they had moved into their neighborhoods in the last two years; 36 percent said they were "almost certain" they would have to move in the next two years.

The study found that many residents, coming under intense pressure to leave their homes, were incapable of resisting because unemployment or underemployment kept them from meeting landlords' demands for higher rents and purchase prices.

In written responses to detailed questions, the blacks and Latinos surveyed described themselves as already pummeled by severe unemployment, street crime, ineffectual public schooling, inadequate and inept government services. On top of this, they indicate they are now being pushed to the wall by the sudden realization among the more affluent that in-town living is chic, comfortable and profitable.

The sketch drawn in cold statistics makes an expectedly grim portrayal of life in six representative areas: the Fort Stanton and Old Uniontown communities in Southeast Washington, northeast Capitol Hill and the 14th Street corridor and Mount Pleasant and Adams-Morgan neighborhoods in the central area of the city.

To anyone walking or driving through these areas, the combined phenomena have become a familiar pattern. Blocks of row houses occupied for decades most often by poor blacks and less frequently by Latinos melt before the advance of wealthier blacks and surprisingly large numbers of whites.

Tumbledown front steps are swept away, replaced by architecturally clean facades. Dreary brick walls are covered in charmingly authentic colonial tones. Real estate prices soar dramatically. What had been a slum has suddenly become a desirable neighborhood. The city is being turned around.

But as the survey makes clear, such a view does not take into consideration those who are being cut down by the two-edged blade of urban renewal. Terming displacement a "volatile crisis," outgoing league president John E. Jacob said it was "nothing new. It's just a more recent example of the historic dispossession of low-income black and Latino families from their rights, rewards and entitlements as District citizens."

What makes the study, entitled "S.O.S. '78 -- Speak Out for Survival," particularly valuable, Jacob said that it "documents this phenomenon tentatively for the first time."

In addition to documenting residents' concerns about housing, unemployment, crime, transportation, schools and publc services, the survey presents a series of challanges to the D.C. government in the form of "recommendations."

Central among these, the league called on Mayor Marion Barry to declare "a strong antidisplacement policy" and for the D.C. Housing and Community Development Department to implement this policy by providing several "transitional neighborhoods with the full range of available programs, resources and techniques for encouraging revitalization and averting displacement."

Spokesmen for Barry and Robert L. Moore, the new director of Housing and Community Development, said neither had yet had the opportunity to study the detailed, 61-page survey and thus had no comment.

William W. Barr, administrator of the Social Rehabilitation Administration of the Department of Human Resources, and chairman of the league's board of directors, warned that unless the government and private sectors responded to the survey's findings, "then, indeed, we are in for trouble."

Carefully pointing out that he did not want to be labeled a "doomsday prophet," Barr said, "We do not have to experience any such horrible problems if we just heed the warnings and move in a timely manner. I have an abiding faith that we will act responsibly as a city."

Speaking during a news conference at the league's offices, Jacob -- who is becoming executive vice president of the National Urban League in New York City -- said the crisis facing Washington's low income neighbors "is not a matter of blacks versus whites or 'haves' verus 'have nots.'"

The issue, he said, was that whites -- as well as more affluent blacks -- were forcing poor residents out of their homes.

Noting that there generally were ample vacant buildings in most transitional neighborhoods, Jacob called on the Barry administration to "encourage" newcomers to rehabilitate these and move into them.

This was a response to the survey's finding that two-thirds of all home-owners interviewed said they had been approached by real estate agents and others seeking to purchase their homes. In reply, 98 percent of those said they would not sell.

Renters were far more susceptible to pressures on them to move than were homeowners.The study also found that tenants' vulnerability was compounded by their inability to afford more rent than they were already paying. With 61 percent of all respondents saying they earned as much as $700 a month after taxes, 68 percent of renters said they were paying more than one-fourth of their income for rent.

In the twin areas of income and employment, the survey found that fully 24 percent of the available work force was out of work. This did not include 7 percent more who were not looking for jobs and were termed "discouraged workers." A league official said these were persons capable of work who had "given up the struggle after being beaten down by the system."

The 24 percent unemployment figure, which comprises blacks and Latinos, is in marked contrast to the city-wide, all races figure of 9.2 percent released by the D.C. Labor Department for the same period as the survey, June 1978. A league spokesman said official figures broken down by race were still not available.

The survey found that unemployment among black (25 percent) was markedly higher than among Latinos (14 percent). Unemployed blacks were also likelier to go jobless more than 26 weeks (86 percent) than Latinos (60 percent).

At the same time, according to the study, Latinos tended to earn considerably less than blacks. Eighty-three percent of Latino heads of household reported annual incomes below $10,000 while the corresponding figure for blacks was 56 percent.

Despite the high unemployment rates, the survey found, only 12 percent of residents questioned said they were receiving Aid to Families with Dependent Children, the government support feature most commonly termed "welfare."

From 50 to 83 percent of all family heads complained that the broad range of key municipal services, including employment counseling and health services were "fair" to "very poor." Adding that they were treated shabbily by staff members of these services, many respondents said they chose not to use them.

"This really ought to dispel the 'welfare' myth,'" Jacob said.

Street crime carried out by youngsters in their neighborhoods proved to be an overwhelming fear and concern. Almost all respondents -- 97 percent -- termed youth crime "a serious problem in D.C." The most feared crimes were robbery (24 percent), burglary (19 percent) and drug abuse (17 percent). Rape was most feared by 11 percent and murder by 10 percent.

In general, the great majority (83 percent) preferred improved prevention activities to increased police patrols (17 percent) as the prime means of dealing with youth crime.

Conversely, 72 percent of all respondents preferred stronger law enforcement as a means of reducing access of drugs and alcohol to youngsters. A league spokesman said this indicated a perception among parents "that drugs and booze are not their doing -- it's seen as a matter of easy availability."

Crime on Metro buses was seen as another problem area. with 91 percent terming it "serious," although just 24 percent said they'd ever been robbed or assaulted on a bus.

Seventy-six percent of the respondents said they "never" rode the subway essentially because the system did not touch their neighborhoods. This led the league to conclude in its findings that "Washington has a separate and unequal transportation system for black and Latino residents of low income District neighborhoods. These citizens are likely to be walking or using the bus while other citizens are driving private cars and taking subways and taxis to work and to shop."