THE FAIRFAX COUNTY schools include at least 2,700 students of limited English abilities, speaking 50 different original languages. The county has mounted an intensive program to immerse the students in English, and reports excellent success: the children come up very quickly to the national average in achievement tests. Wonderful, right? Wrong, according to officials of the Office of Civil Rights, recently of HEW, now of the Department of Education. This office has been carrying on a running tiff with the Fairfax County schools -- and more than 300 other school districts around the country -- over whether such programs comply with the Title VI of the Civil Rights Act of 1964.

This situation is patently absurd. It is the product of the creeping politicization over the last decade of federal efforts to ensure equal educational opportunity to chidren with limited English. More than 70 percent of the estimated 3.6 million schoolchildren whose first language is other than English come from Hispanic homes, and the issue of bilingual education has become a potent political focal point for Hispanic leaders.

In 1974, the Supreme Court, in the landmark Lau v. Nichols decision, found San Francisco in violation of the Civil Rights Act: the city had not made special efforts to ensure that some 1,800 Chinese-speaking students understood what they were being taught. The court insisted that something must be done, even while it clearly stated that no single remedy was prescribed.

This is where things got off the track. The Office of Civil Rights set up a task force to design guidelines for the "something." The guidelines, known as the "Lau remedies," have never been published as regulations or enacted as statute. They have been in use since 1975, however, and they are the reason for the trouble experienced by Fairfax County and its 300 fellow school districts. The guidelines, contrary to the Supreme Court decision, do prescribe a single method of teaching: a school district with 20 or more students from any non-English-speaking group must provide transitional bilingual-bicultural education to all elementary school children who speak primarily the native tongue, and to all intermediate-level students who do not speak English. Intensive English as a Second Language (ESL) programs, as in Fairfax, will not suffice.

One might expect such categorical certainty would be based on strong evidence of what helps students. Not true. As Noel Epstein has observed in his monograph on the subject, the "Lau remedies" not only do not follow the court decision, but they also have no solid educational basis. In 1968, a Bilingual Education Act was established to fund projects that would demonstrate successful methods of teaching children whose first language is not English.After 12 years, the evidenced is still muddled.

The fact is that there still has been no effort to assess the relative merits of different approaches for different types of children. This is lamentable, if only because the number of such children has grown significantly in the interim. The funds went, instead, to a range of service programs; some of these put more emphasis on maintaining a student's proficiency in his native language and teaching him about his ethnic heritage than on getting him through a transition to working in English at school.

One reason lies in the difficulty of finding enough genuinely bilingual teachers to staff transitional programs. Another is that some Hispanic leaders show a political commitment to forcing the use of Spanish in the school system. It is claimed that such programs have value as teaching devices in some situations, but no evidence of this now exists.

The Department of Education has announced it will issue formal regulations to remedy the "remedies." This promises to be an interesting exercise since Secretary Shirley Hufstedler herself, during her former career as a federal judge, established the principles for the Lau decision. We believe that the new regulations should go back precisely to that decision. Also, some portion of the $192 million slated for bilingual education projects in 1981 should go into careful studies of the effectiveness of various teaching methods for students in varying circumstances.

The federal government should not impose curricula on local school districts. It should limit its regulation of bilingual education to making certain, as the Supreme Court has ruled, that something is done. The single criterion for that "something" should be success for the children involved. By that criterion, by the way, Fairfax County looks pretty good.