MANY CITIES require that their employees be residents of the city that provides them jobs. There are many good reasons for such a policy and many disadvantages too. Local taxpayers like to think that jobs the city pays for should stay in the community. Others believe that a familiarity with the town or city, its customs and families, helps a civil servant do a better job. And when the people who run a town and work for it have a stake in seeing that services are provided and money isn't wasted, that's a plus.

There is a residency requirement in the District of Columbia that was imposed for many of these reasons and also because it gives something of a preference to those in the local employment pool, which is primarily black. Nevertheless, the policy has been extremely controversial mainly because of the high cost of housing in this city -- so high that most civil servants, police and firemen cannot afford to live here. Our system, like most in the country, though, does not restrict jobs to current residents. Instead, qualified persons can be hired and can keep their jobs so long as they move into the city within a specified period of time. The policy was not designed to exclude members of one race from holding city jobs.

That is not the case in seven Chicago suburbs, the government charged in a case filed this week in federal court there. These Cook County municipalities -- Berwyn, Dolton, Elmwood Park, Forest Park, Melrose Park, Niles and South Holland -- employ some 1,143 persons, not one of whom was black at the time the Justice Department began its investigation earlier this year. The department alleges, in fact, that no black has ever been a regular employee of any of these towns. None of the seven has a substantial black population, and each has a residency requirement that the department alleges was designed to keep blacks from holding public jobs. All require that applicants be current residents, and some even have durational requirements. In Elmwood Park, for example, those seeking police or firefighter jobs have to have lived in the town for three years; in Melrose Park they would have to have been residents for five years.

The Justice Department believes that there is no valid purpose for such regulations and that they were intentionally designed to provide a legitimate veneer to what is really racial discrimination. If that is proved, the regulations surely must be invalidated just as more overt employment discrimination has been struck down since 1964. It's an interesting and novel lawsuit, and the administration did well to bring it.