One or more persons living together in a single dwelling unit as a traditional family or the functional equivalent of a traditional family. It shall be a rebuttable presumption that four or more persons living together in a single dwelling unit, who are not related by blood, adoption, or marriage, do not constitute the functional equivalent of a traditional family. In determining the functional equivalent of a traditional family, the following criteria shall be present:
[Amended 1-5-1988 by L.L. No. 1-1988; at time of adoption of Code (see Ch. 1, General Provisions, Art. I)]