What is an accessory dwelling unit (ADU)?

An ADU (accessory dwelling unit) is an additional, self-contained dwelling on a typical single-family lot. It can be attached, such as in the lower level of the main dwelling, or detached at the rear of the property. These smaller units represent the “missing middle,” filling the gap between single-family homes and multi-unit dwellings downtown. While ADUs are not the sole answer to Decatur’s missing middle, they represent a big step in the right direction. Residents of ADUs contribute to the vitality of the community, and ADUs make it possible for more families to own and maintain a home in the city.

ADUs as a housing type became effective in 2015 upon adoption of the Decatur Unified Development Ordinance. They are allowed in most single-family and multi-family residential zoning districts – R-85, R-60, R-50, RM-18, RM-22, and RM-43. One ADU per primary dwelling unit is possible if the lot conforms to the minimum size requirements of its zoning district.

Other considerations:
An ADU may be developed in or to the rear of an existing or new main dwelling. To keep true to its accessory size, an ADU may have a floor area up to 800 square feet, and should not exceed 40 percent of the floor area of the primary dwelling. If the ADU is combined with the garage, the total floor area may be up to 1,000 square feet. An ADU may have up to two bedrooms. The owner is required to reside in either the main dwelling or the ADU for at least eight months of the year; an affidavit will be required of the owner confirming residency. If detached from the main dwelling, an ADU must be located in the rear yard and have a footprint no greater than 30 percent of the rear yard. In combination with the main dwelling, the total floor area should not exceed 40 percent of the lot area. Similarly, the total lot coverage of all impervious surfaces should not exceed 40 percent of the lot area.

As a housing option, ADUs demonstrate the values of diversity and affordability promoted by the City of Decatur. They serve to fill a gap in Decatur’s housing market by providing a new, neighborhood scale rental housing option for those looking for affordable living arrangements in a more traditional single-family-home setting.

The One Atlanta: Housing Affordability Action Plan outlines a bold vision to achieve Mayor Bottoms’ vision to provide a pathway to affordable and equitable housing opportunities for all who desire to call Atlanta home. 

Atlanta’s population is increasing, but new housing construction has focused on higher-cost demand.
In 2017, Atlanta was the third fastest growing metropolitan region in the United States. As our population grows, many of our long-term residents are experiencing challenges related to affordable housing, particularly as much of the new residential development has focus on higher-cost units.
While our economy has grown over the last decade, wages have not kept pace with rising rents.
Between 2000 and 2017, Atlanta’s median rent increased by over 70%, but Atlanta’s median income only increased by 48%.
There is a growing gap between what people can afford versus what people are making.
As housing costs have grown, more Atlantans have been forced to spend a greater percentage of their income on housing costs. In 2016, more than half of Atlantans were considered housing-cost burdened.