Accessory Dwellings



The Northern Virginia Association of Realtors® (NVAR) supports expanding opportunities for homeowners to build and utilize accessory dwelling units while maintaining government oversight to effectively address concerns of residents and maintain communities.   

Policy Positions Long Banner (345 x 900 px) (1)


Increasing the supply of affordable housing is a challenge for localities across Northern Virginia and throughout the region.  While local governments have focused a lot of effort on the traditional route of providing financial subsidies and incentives for the development of committed affordable units, other options include measures to increase housing density in order to put more housing on a limited supply of available land.

One option that is increasingly being recognized as an effective means of addressing the nationwide shortage of affordable rental housing is to allow accessory dwelling units in neighborhoods that are predominantly single-family. An accessory dwelling unit is defined as a smaller (subordinate to the primary home), independent residential dwelling unit located on the same lot as a single-family home. These may be known as “granny flats,” “mother-in-law apartments,” “carriage houses,” “guest houses,” “English basements,” or numerous other terms. 

Accessory dwellings have potential to increase the supply of affordable housing because they can increase the availability of housing by leveraging the existing housing stock on already developed land. They also disperse affordable housing, rather than concentrate it in a few areas. The market for the affordable housing provided by accessory dwellings is large and diverse. The American household is no longer defined solely by the model of two parents living with children. Today, the average American household consists of only 2.6 people. Americans are marrying later in life, or they are living alone or with a partner. People are

also living longer and many find that they no longer need or want the space of a traditional single-family home. Accessory dwellings are also useful for families who want to help other family members live nearby, but who want them to have a separate residence. A homeowner may want to furnish a living space for his or her parents, or may want to make sure a child who has just started to work and be independent has a decent place to live while still not living “at home.”

Much of the opposition to accessory dwellings comes from residents afraid that allowing them in their residential neighborhoods will bring about increased traffic and crowding, and may attract transient

residents who will drive down the values of other properties. There is no evidence to support these claims, especially if local zoning ordinances are drafted to provide limits on dwelling size, total number of occupants, and lot size while requiring community infrastructure such as parking.

Well-crafted ordinances that accommodate both the rights of property owners who wish to add an accessory dwelling and the concerns of their neighbors are critical to the success of accessory dwellings in the affordable housing market.


NVAR supports the adoption of ordinances expanding the ability for homeowners to build and utilize accessory dwelling units while maintaining county oversight to limit negative impacts on residential neighborhoods and ensure adequate parking and infrastructure exists to support the accessory use.



The Arlington County Board adopted new standards that permitted the establishment of new detached accessory dwellings and increased flexibility for homeowners to convert their existing accessory building into a detached accessory dwelling. Fairfax County and the City of Alexandria are studying accessory dwellings. Alexandria does not currently address accessory dwellings in their zoning ordinance.  The Fairfax County accessory dwelling ordinance has been in place since 1986. The law requires a special permit approved by the Board of Supervisors and is subject to limits such as the requirement that those residing in the unit must be over the age of 55 or have a permanent disability. A new proposal would remove age and disability requirements and simplifies the approval process for obtaining a permit.