The Virginia Supreme Court ruled today that group homes for mentally retarded adults cannot qualify as "single family" housing if a counselor lives with the group, a decision that some group home advocates said will slow efforts to establish more of the homes in residential neighborhoods.

"I find it a very disappointing decision," said Lewis Zieske, executive director of the Virginia Association for Retarded Citizens, a statewide group that has helped push for increased use of the homes for mentally retarded persons. "I think the courts were led to a very poor understanding of what a group home is."

Northern Virginia officials said they fear the ruling means that a home with as few as three retarded residents and a counselor would have to obtain a special permit to be in residential neighborhoods -- a step that neither Fairfax nor Arlington county now requires. In Alexandria, all group homes for mentally retarded adults, regardless of the size, must obtain such a permit from city officials.

Advocacy groups say counselors are crucial to the success of group homes and have fought permit requirements, arguing that the hearings they bring often make the homes the subject of community protests, making it difficult, sometimes impossible, to establish group homes in residential neighborhoods.

"This may change our outlook on the whole procedure," said John V. Callaghan, who heads Fairfax County's group residential facilities program. "It's a tricky issue. When you start requiring permits and hearings, you throw a monkey wrench into the thing. You put the homes under undue scrutiny."

The Virginia Supreme Court's 7-to-1 ruling today upheld a lower court ruling in favor of homeowners who filed suit to block construction of two homes for mentally retarded adults in Chesterfield County, suburban Richmond.

Each home was to include four mentally retarded adults and a full-time counselor. The homes were intended "to provide mentally retarded adults with normal residential housing in a community setting including the activities and life style incident to such a setting," according to the Omega Corp. of Chesterfield, a nonprofit organization that owned the two lots and planned to build the homes.

Homeowners in the two communities challenged the plan in Chesterfield County Circuit Court, contending that their subdivision covenants restricted housing to single family residences.

Omega disagreed, saying that the covenants dealt with the type of buildings to be constructed and whether they were used for residential purposes, not with the type of individuals who would live in them. Omega said the homes would look like most others in the neighborhood.

Omega argued in court that the term "family" should be broadly interpreted, or else other groups -- like three unrelated school teachers or a family with a live-in maid -- would not be alllowed to live in the neighborhood.

"We agree with Omega that the word 'family' should be interpreted broadly," said the Virginia Supreme Court. But the court said that the "presence of counselors in the homes and their supervision of the occupants would convert what might otherwise have been a single-family use into what the lower court trial judge termed a facility."

The group house proposed by Omega would "require that we apply an unrealistic meaning to the word 'family,' " said the court. "We can conceive of nothing more antiethical to the concept of family home life than the constant surveillance of purported family members by government employes assigned to supervise them."

That point troubled many of the mental health experts who say that without the assistance and supervision of professional help, the group homes would not succeed and could become a nuisance to the neighborhoods.

The court's lone dissent came from Justice John Charles Thomas, an appointee of Gov. Charles S. Robb. Thomas called the opinion "bad law which will prove unworkable." He sided with Omega in the view that the covenant applied only to the type of building and not its use.

He also praised the role of counselors, saying: "In my view, watching over and supervising members of a family who need such attention is central to family life."

Thomas said the majority opinon was a "sharp departure" from previous rulings on real estate covenants in which the Virginia court had focused on "precise language" of any restrictions. He said those rulings were resolved in favor of free use of the property in cases where covenants were ambiguous or in substantial doubt.

Virginia Association for Retarded Citizens' Zieske said: "It's really unfortunate that anybody would use the word surveillance in that context. Their counselor's function is to help residents train to live more independently. It's not like a jailer. The word surveillance sounds like you're talking about prisoners. That is contrary to community residential placement."

Zieske said his group would try to get the Virginia General Assembly to change the law in January when the 1985 session convenes.