Brit Webb, superintendent of the tiny Buena Vista school district in the west Texas town of Imperial, got a letter from the Department of Education a few months ago.

It told Webb someone had complained that his school's dress code violated federal civil rights regulations. But the letter added that the secretary of education was trying to eliminate the rule and the department would let Webb know what happened.

He's still waiting, because the federal dress code rule lives on, more than a year after Education Secretary Terrel H. Bell announced with some fanfare that he was killing it--and more than six years after a secretary of health, education and welfare first said somebody should.

The seemingly simple job of deleting a few lines of Section 106.31 (b) of the so-called Title IX sex discrimination regulations--which prohibit discrimination "in the application of codes of personal appearance"--has been hung up for months in the regulatory bureaucracy.

Advocates of deregulation say the delay isn't an impressive example of what the Reagan administration promises to accomplish.

Sheldon Steinbach, general counsel for the American Council on Education, an umbrella group of colleges, said, "If the administration cannot make reasonable progress on a simple issue such as dress codes, how can we expect them to accomplish regulatory reform on more complex matters?" Steinbach's group has its own agenda of regulatory reform issues on which he says the department has made little progress.

Gwen Gregory, an attorney for the National School Boards Association, said, "How are they going to do something complicated and controversial like 94-142 the law providing for the education of handicapped children if they can't do the easy ones?"

Webb, whose school is the only one in the nation that has had a dress code complaint lodged against it so far this year, said he agrees with Bell's attempt to kill the regulation. "It's not a problem until they federal officials make it one," he said.

He added that there have been few complaints from the 200 students about the rules that require them to dress "in a manner not distracting to others." The department will not name the source of the complaint.

"We're not that strict," he said. "They can grow beards and mustaches."

Bell launched his campaign against the regulation in April, 1981. He announced that by eliminating the rule, he was eliminating "unnecessary and inappropriate" government interference in the affairs of local communities. It was "plain silly" for the federal government to be involved in such matters, he said.

Education officials point to the Justice Department's civil rights division as the cause of the delay. The regulation has been sitting there since last October, they said.

Before sending it over to Justice, the Education Department had received more than 50 comments on the proposal. Most favored killing the rule, but representatives of women's groups and an Indian rights organization supported it, saying that local codes often restricted their freedom.

In February, Justice told Education officials that they should delete a reference in the final rule's preamble that claimed that killing the regulation would reduce record-keeping burdens.

William Bradford Reynolds, assistant attorney general for civil rights, wrote Education general counsel Daniel Oliver that "We are unaware . . . of any reporting burden under the old rule." A week later Education agreed to drop the reference. It still awaits approval from Justice's coordination and review unit. Then the Office of Management and Budget must approve it, too.

The saga of the dress code regulations dates back to the Ford administration, shortly after the Title IX rules were issued in 1974. HEW Secretary David Mathews asked aides in the fall of 1976: "Is there any way we can get out of that hair business? With all of the pressing needs in civil rights, I really hate to see our time and resources diverted to a subject that frankly does not seem to me to be of the priority of some of our other obligations."

When Joseph A. Califano took over HEW in 1977, he looked at a memo on the subject and shot off a note saying, "This whole subject is nonsense. . . . What the hell are we involved in a subject like this for? There are a lot more important things for the office for civil rights to spend its time on. . . . " The next year the process of rescinding the rule began.

But when Califano was fired and succeeded by Patricia Roberts Harris, the tide turned again. She issued a press release in 1979 saying the rule would be enforced after all and 78 complaints would be processed. No action was taken against any school district, however, before the 1980 election. Only a handful of complaints, including the one against Buena Vista, have been filed since .