Over half of Cobb County’s cities now allow accessory dwelling units (ADUs) on single-family residential lots, while a similar proposal for unincorporated Cobb remains stalled due to public opposition.
ADUs, also known as secondary suites or granny flats, are independent residential units located on the same lot as a detached single-family home. These structures can be attached or detached from the main residence and are often used for affordable or multigenerational housing.
Mableton is the latest city to permit ADUs, officially called habitable accessory dwelling units (HADUs), after taking control of planning and zoning enforcement in March 2025. Other cities allowing such dwellings include Acworth, Marietta, and Powder Springs.
In November 2024, county officials tabled a proposal to allow ADUs in unincorporated Cobb following significant public backlash. Concerns cited by opponents include increased traffic, overcrowding, and changes to neighborhood character. “…undermine the fabric of what we’ve had here in Cobb County for a long time,” said Cobb County Planning Commissioner Fred Beloin when rejecting the county’s ADU proposal.
Each city has established its own regulations:
– In Acworth, garden cottages (detached) and accessory suites (attached) are permitted. Only one ADU per lot is allowed; it cannot exceed half the size of the primary structure and must meet location and privacy requirements.
– Mableton allows both attached and detached HADUs with separate living facilities. Units cannot exceed 1,000 square feet in heated space or 16 feet in height and must provide additional parking.
– Marietta permits one attached or detached ADU per property but does not allow renting or leasing these units. The footprint cannot exceed half that of the main house.
– Powder Springs allows one accessory apartment per lot, either attached or detached. The unit must range between 680 and 1,000 square feet (or less than the main house), match the design of the primary building, and provide extra off-street parking.
Kennesaw is considering an ordinance to allow ADUs in several residential districts. Zoning administrator Darryl Simmons led three town hall meetings seeking public input on proposed guidelines similar to those in other Cobb cities: “We are still looking at other jurisdictions. We’re looking at, you know, definitions, we’re looking at what other things we can add or subtract from our research that would make it something that’s feasible, something that is defendable in court, and something that makes sense,” Simmons said.
A date for Kennesaw’s final ordinance presentation has not been set as research continues. Residents can participate in an online survey about ADUs at https://docs.google.com/forms/d/e/1FAIpQLScJHmEHrhOZsk9OfQddYFb4fRFdvbpuLFBnr9oVm2KbTlygZQ/viewform.
Questions about Kennesaw’s proposed ordinance can be directed to Kennesaw Planning and Zoning at 770-590-8268 or zoning@kennesaw-ga.gov.
