A month-old ban on new rentals to families with children at one of Columbia's oldest apartment complexes violates Howard County's landmark antidiscrimination law, the County Council's vice chairwoman and a coalition of human-service agencies charged today.

Vice Chairwoman Elizabeth Bobo and a spokeswoman for the Association of Community Services, which represents 75 agencies and individuals across the county, said the all-adults policy at the 300-unit Tilbury Woods apartment complex violates a 1975 statute prohibiting discrimination on the basis of a person's age.

"It's pretty clear that the all-adult rule violates the law," which is widely regarded as one of the most liberal antidiscrimination statutes in Maryland, said Bobo. Her comment came as public pressure mounted against the Krupp Co., a Boston-based realty firm that plans to convert Tilbury Woods and a neighboring 60-unit complex into all-adult housing.

Krupp bought Tilbury Woods, Oakland Meadows and three other Columbia apartment complexes earlier this year and announced that it would not rent to families with children. Despite assurances from the company, some current tenants said they fear their leases will not be renewed because they have children.

"The all-adult policy violates the antidiscrimination law. . . and may have the effect of discriminating against minorities" in particular, said Amy L. Reisch, a director of the community services association. Twelve association directors voted unanimously today to ask the Copand the law's scope to include families as a "protected class."

The law, amended earlier this year, prohibn on the basis of age, race, sex, creed, religion, appearance or sexual preference.

The association also haCounty Commission on Human Rights to file a formal discrimination complaint against Krupp for its all-adults rommission, which officials said had received no formal complaint about the new policy, recently opened informao the matter.

Jack Davenport, a Krupp Co. vice president, said he was not aware of the antidiscrimination law, adding that the new policy at Tilbury Woods "in no way" violates the statute.

Rather, he said, the all-adult rulewas "a response to a significant market demand"--one for adult units now scarce in Columbia.

In recent weeks, an estimated 500 people inquhe Krupp Co.'s local office about rental space and more than 70 percent of them sought all-adult complexes, Davenport said from his Boston office.