Notwithstanding any other provisions of this chapter, an accessory family dwelling unit in an owner-occupied, single-family residence shall be permitted as a reasonable accommodation only for family members with disabilities. The appearance of the structure shall remain that of a single-family residence, and there shall be an internal means of egress between the principal unit and the accessory family dwelling unit. If possible, no additional exterior entrances should be added. Where additional entrance is required, placement should generally be in the rear or side of the structure. When the structure is serviced by an individual sewage disposal system, the applicant shall have the existing or any new system approved by the Department of Environmental Management. The Zoning Enforcement Officer shall require that a declaration of the accessory family dwelling unit for the family member or members and its restrictions be recorded in the land evidence records and filed with the Zoning Enforcement Officer and the Building Official. Once the family member or members with disabilities no longer resides in the premises on a permanent basis or the title is transferred, the property owner shall notify the Zoning Official in writing, and the accessory family dwelling unit shall no longer be permitted, unless there is a subsequent valid application.