Arlington Moves to Encourage Accessory Dwellings

Published on November 28, 2017


  • Board votes to promote housing diversity across Arlington, support aging in place

  • Removes  Zoning Ordinance obstacles while maintaining neighborhood character

  • Allows detached accessory dwellings in existing detached accessory buildings


The Arlington County Board on November 27 adopted amendments to the Zoning Ordinance aimed at making it easier to create accessory dwellings in single-family neighborhoods.

"The ordinance we passed in 2008 failed to generate accessory dwellings," Arlington County Board Chair Jay Fisette said. "We are committed to creating more affordable housing in our County, and to making it easier for Arlingtonians to age in place. An accessory dwelling could create an additional income stream for those on fixed incomes. These revisions will give homeowners more opportunities to create accessory dwellings, while maintaining the character of our single-family neighborhoods."

The Board voted 4 to 1 to approve the revised ordinance. Board Member John Vihstadt voted no.

The revisions adopted by the Board would, among other things:

  • Put no limit on the size of an accessory dwelling wholly within a basement;

  • Require that an accessory dwelling take up no more than either 35 percent of the combined floor area of the main and accessory dwelling, or up to a maximum of 750 square feet;

  • Allow detached accessory dwellings in existing accessory buildings; assess more options for setback requirements for new detached accessory dwellings;

  • Remove annual limit on the number of accessory dwellings that can be created in the County; and

  • Require owner occupancy; however, if the owner does not occupy one of the dwellings, the entire property may be occupied by no more than one family;


The Board directed the County Manager to bring it more options on setbacks for new detached accessory dwellings and, in the coming months, will consider whether to further revise the regulations  to allow them in the coming months.

Advancing the goals of the Affordable Housing Master Plan


The revisions to the Accessory Dwelling Ordinance are in keeping with the goals of the County's 2015 Affordable Housing Master Plan (AHMP), an element of the County's Comprehensive Plan. The AHMP, the County's long-range vision for addressing housing needs, calls for the County to explore zoning regulations that allow and promote a wider diversity of housing and household types in single-family neighborhoods. The goal is to help meet the evolving needs of families and households while maintaining neighborhood character and underlying zoning.

Accessory dwellings were identified in the plan as a tool to help achieve this goal, and the plan's implementation framework recommended that the County revise the regulations to encourage accessory dwellings. The Board first voted in 2008 to allow accessory dwellings inside existing homes, with tight restrictions. The original ordinance has yielded just 20 accessory dwellings across the County

The Board held a public hearing in October before voting to advertise a public hearing the proposed changes. Some of the feedback offered by the public at that meeting was incorporated into the regulations the Board adopted.

Public engagement


A working group provided feedback to staff on potential changes to the accessory dwelling regulations. The group's meetings were open to the public. Community engagement began in Fall 2016 with a Missing Middle Design Gallery co-hosted by the Alliance for Housing Solutions.

Staff also developed a website and educational materials, and had a booth at the Arlington Home Show and Expo in April 2017. The County held a community forum in May, 2017, and the feedback from the forum informed staff's preliminary recommendations. The County conducted a community survey on the draft recommendations in June and July 2017, and the Board held a work session in July. Several advisory commissions reviewed the recommendations.

Visit the County website for more information on the public process for updating the County's Accessory Dwelling regulations.

To read the staff report, scroll down to Item No. 49 on the agenda for the Monday, Nov. 28, 2017 Carryover County Board Meeting.