The U.S. Civil Rights Commission, in a somewhat gloomy report, yesterday labeled 1979 a year of "drift" in civil rights, relieved occasionally by "positive initiatives."

The commission, headed by former health, education and welfare secretary Arthur S. Flemming, said that 25 years after the Supreme Court outlawed public school segregation, nearly half of all minority-group schoolchildren remain in "racially isolated schiols" -- and Congress through antibusing and other legislative riders has prevented federal agencies from taking action to offset this.

The commission also charged that "housing discrimination remains widespread throughout the United States," with a "grim pattern indicating that minority families and those headed by women pay disproportionately high costs for flawed, deteriorating and overcrowded housing."

It was particulalry critical of the Carter administration and Congress for providing funds for only about 257,000 new subsidized rental units for the poor in the current fiscal year -- a time when it said poor people cannot afford high interest and construction charges to build their houses and when rental vacancies, nationwide are extremely low. The commission said the 1968 federal housing act set a goal of 600,000 units a year which has never been met.

The commission also said employment rates for minority-group members and women still lag "significantly behind" those of white men.

"During the third quarter of 1979 the unemployment rate for black males 20 and over was 8.3 percent, and 5.5 percent for Hispanics compared with 3.3 percent for white males," for example.

"The 1960s brought us good laws," said the commission in issuing its report on the 51st anniversary of the birth of the Rev. Martin Luther King Jr., "and they were enhanced in the 1970s by strong judicial decisions.

"Yet the lack of enforcement by the executive branch of government, the weakening of good legislation by Congress, and the diminishing will and vision on the part of many Americans are discouraging."

While it saw relatively little progress in most areas, the commission said there were some hopeful rulings and developments.

In housing, it cited administration support for beefing up federal antidiscrimination laws (which it endorsed). In education, it praised a Supreme Court ruling upholding findings of intentional segregation by the Dayton and Columbus, Ohio, school systems; defeat of a proposed constitutional amendment against school busing and of several other attempts in Congress to further restrict federal agencies' efforts to foster desegregation, and the elevation of the director of the Office for Civil Rights to the status of an assistant secretary in the new federal Department of Education.

In employment, it was happy with the Supreme Court's Weber decision, holding that voluntary affirmative action programs could be established even though there was no prior finding of discrimination by the company or union, and with new acton guidelines set by the Equal Employment Opportunity Commission.

The commission concluded: "Segregated school systems will continue to operate in many communities [and] widespread discrimination in employment [and] housing will continue into the '80s" unless enforcement efforts against discrimination are considerably strengthened.