• An ALU contains areas for eating, sleeping, living, and sanitation, and is occupied by somebody as their residence.  
  • Examples include arrangements known as in-law suites, backyard cottages, basement apartments, and other terms.
  • Can provide for flexible living arrangements for extended family members, live-in childcare providers, caretakers, renters, or other similar situations.
  • ALUs are subject to the Zoning Ordinance requirements of 4102.7.B, which include limitations related to size, number of people, entrances, owner-occupancy, parking, and other standards.
  • An ALU provides for long-term occupancy, and a property with an ALU cannot also have short-term lodging.
  • Interior ALUs require either an administrative permit approved by staff or a special permit approved by the Board of Zoning Appeals following a public hearing to modify certain standards, such as the size of the unit or parking.
  • Detached ALUs are only allowed on lots with 2+ acres with special permit approval.
  • There are currently approximately 158 approved ALUs in Fairfax County. This represents 0.08% of the number of single-family detached dwellings.