MONTGOMERY COUNTY has 950 public- housing units, two-thirds of which are at scattered sites and one-third in clusters. Over the years the clustered units have become disproportionately black. The public-housing program in the county serves mainly blacks in any case. Whites are 85 percent of the population and a majority of the county's poor, but only 30 percent of the public-housing applicants. They now also make up less than 15 percent of the tenants in most of the clusters. Rather than go to the clusters, whites have often given up their places on the public-housing waiting lists.

The county's Housing Opportunities Commission has been uncomfortable with this pattern for all the reasons you would expect. The commission does not want to foster racial segregation, as too many public housing projects have over the years. It also hopes, although funding has dried up for now, to have the means someday to build more units, including some in small clusters. It is always hard to find a site for public housing, a community willing to accept new units in its midst. It is all the harder in white communities if the units are likely to be all or nearly all black, county housing officials ruefully say.

For some time, to combat this, the commission has had a policy of moving whites up the waiting list so that new clusters start out half white and half black. Early this year it also adopted an "integration maintenance" plan for the clusters. The plan is a compromise; it carefully does not set inflexible racial quotas. But it does set strong racial goals and, in a perverse way, grants racial preferences. If a cluster is over 70 percent black, and the next applicant on the list is black, he will be passed over. The agency will go down the list until it finds a white. If the white turns the unit down, he loses his place on the list and the unit goes to the black who was passed over. If the white moves in, the black whose application was delayed is offered the next available unit, even if it is in a cluster already heavily black. The commission has thus limited itself. Only once per vacancy will it try to alter a cluster's racial mix; only once can a given black applicant be bumped from the top of the list. The vacancy rate is such that a passed-over applicant will generally be offered a second unit in less than a month, director Bernard Tetreault says.

Several other housing agencies across the country have resorted to integration maintenance plans for about the same reasons. The plans have been submitted to the Department of Housing and Urban Development, which has not ruled. No one can quarrel with the goals of these plans -- an integrated society, fewer problems for future public housing. The Montgomery officials have made their plan as gentle as they could.

But they have skipped past a vital distinction. The courts have said policies based on race may be used to overcome the effects of past racial discrimination. That is as it should be; there is often no other way. Here a policy has been formulated instead to support a social preference, to fine-tune a racial result, and that is wrong. Race has no place on these waiting lists.