just about any family in Fairfax County can wake up one morning to find as next-door neighbors a house full of emotionally disturbed teenagers.

Yesterday, the county Board of Supervisors, acting on citizens' complaints, took aim at existing zoning laws that define such a group of teenagers, supervised by rotating shifts of counselors, as a family.

Because they are legally a family, according to zoning administrator Gilbert R. Knowlton, neighbors have no right to stop them from moving into residential neighborhoods or even to be warned that they are coming.

In persuading the board to ask the county executive to come up with a zoning law change that would require public hearings and special-use permits for group homes, Supervisors Martha V. Pennino (D-Centreville) said, "The rights of the citizens of this county must be protected. They have to know what is going on."

Citizens in the Ravenwood Park section of the county, where homes are valued from $70,000 to more than $150,000, said they were not warned when six emotionally disturbed teenagers moved into a "therapeutic family home" in their neighborhood this spring.

They have appealed the zoning administrator's ruling about the definition of a family to the county Board of Zoning Appeals and complained to Supervisor Alan H. Magazine (D-Mason).

Other county residents according to supervisors at yesterday's board meeting , have complained about the supervision given the teen-agers and about the teen-agers' impact on other children in the county. Noise, traffic congestion and the youth of some counselors also have been cited.

There are 33 residential care homes in Fairfax providing community-based treatment for children and adults with problems including retardation, alcoholism and emotional ailments, according to the county's Office of Research and Statistics.

Three of these homes, with supervisors said have been the subjects of many complaints in the last two months, are run by Enviroments for Human Services, an Arlington firm that contracts with the county to take care of 20 emotionally disturbed children. The company runs the home in Ravenwood Park and two others in the Springfield area.

John Bryant, administrative director of EHS, says that community complaints about the homes are strikingly similar and adds, "Everyone says it is a wonderful program - in another neighborhood."

Btyant, who refused yesterday to comment on the board's request for a change in the zoning law, said 80 percent of the counselors in the houses have B.A. degrees in social science fields and that he has not received any recent complaints about the way the houses are run.

The number of group homes in Virginia has increased, according to state officials, since a law passed last year prohibited sending children outside the state without the specific approval of the state commissioner of welfare.

Supervisor Pennino said yesterday she thought the idea of community treatment for disturbed children was a sound one, but that it is "absolutely appalling" that these "profit-making" homes can come into a neighborhood without the knowledge or approval of the neighbors.

In other action, the board agreed to an ou-of-court settlement of a long-running dispute over maintenance of several roads in predominantly black communities.

Under the agreement, which still must be approved by U.S. District Court, the county has promised to upgrade some 32 substandard roads, known as "P-6 roads," in mostly black communities over the next 10 years at a cost of $1.5 million.

The agreement resulted from a law-suit filed against the county in 1971 by the Countywide Black Citizens Association and others claiming discrimination byVirginia and Fair ax in pro-communities.