The Montgomery County government may allow health-care organizations to purchase certain moderate-priced town houses for groups of mentally retarded persons or former psychiatric patients.

The town houses are in subdivisions where developers have been granted the right to build additional units in exchange for selling some at moderate prices to qualified families.

Before the health-care organizations can buy the town houses, County Executive Charles W. Gilchrist would have to amend an existing regulation.

As the law is now written, nonprofit organizations and agencies such as the county's Housing Opportunities Commission may buy the newly built town houses at below-market prices and then sell them to families with moderate incomes.

The present law also requires buyers to live in the houses. (The current prices range from about $45,000 for a two-bedroom house to $58,000 for a four-bedroom house.)

Housing department officials say the revised regulation would allow nonprofit health organizations to buy the moderate-priced units or lease them from an agency such as HOC. Organizations' requests to buy the units would be reviewed on a case-by-case basis by the county executive, said Glenn Kregar, the senior housing planner who wrote the revised rule.

He said the housing department has had heard little opposition to the proposal, although some county residents have wanted to know why there was no public hearing on it.

Because the county executive already may authorize the purchase of the units by organizations, there is no need for a hearing to discuss the expansion of that authority, Kregar said.

"We're only talking about a small number of units scattered throughout the county," he added.

The rule change was initiated by County Council member Ruth Spector, who was approached by the staff at St. Luke's House, a residential program for persons recently released from mental institutions. That program, which serves 41 adults in four houses and several apartments around the county, wants more space.

Joan Peterson, director of St. Luke's House, said his organization expects to house three or four people in the new town houses, which the group would lease to the residents.

The Montgomery County Association for Retarded Citizens also has expressed interest in acquiring low-cost housing for its clients, director William Baber said. The organization now houses 106 persons in 30 residences, but owns only eight of those, Baber said. There are 350 clients on the association's housing waiting list, he added.

Baber said that since the association has limited resources, money to purchase the moderate-priced units might be hard to get.

He and Peterson both said their organizations might have to consider renting the low-cost homes from a housing development organization.