Bloomberg Philanthropies will give Chattanooga $450,000 to $750,000 to get more accessory dwelling units built. The goal: approvals in half the time within two years.

Chattanooga will get between $450,000 and $750,000 from Bloomberg Philanthropies to help homeowners add accessory dwelling units, the small second homes sometimes called granny flats or carriage houses. Mayor Tim Kelly announced the award Friday.

The city is among the first local governments picked for a new Bloomberg Philanthropies housing program, according to the mayor’s office announcement. Up to 30 cities will take part. Each gets money and expert help to copy a housing reform that has already worked somewhere else.

Why the city wants it

The City Council voted in May 2022 to let homeowners on single-family lots build an accessory dwelling unit, the city said at the time. Kelly said few have been built since.

“We were excited to get the legislation passed to allow Chattanoogans to build Accessory Dwelling Units during my first term, but I have been disappointed by the relatively small number of units added to our housing stock thus far,” Kelly said in the announcement.

He said the program would help the city adapt reforms “already proven in Austin,” Texas, “with the means to turn a right on paper into more homes on the ground.”

The city has not published a count of accessory dwelling units built since the 2022 vote.

What the money pays for

The announcement said Chattanooga will use the grant for:

  • testing technology to clear approvals faster
  • hiring architects to draw permit-ready plans
  • hiring staff for a housing “strike team”

Accelerator for America, a national nonprofit, will provide hands-on support. City officials will also compare notes with other cities in the program.

The city set three goals for the next two years:

  • cut approval times in half
  • double the number of accessory dwelling units in the pipeline
  • show gains in housing supply across the city

Where the ideas come from

The Bloomberg program is built on three city models, the announcement said:

  • Austin, Texas: legalized up to three homes on most single-family lots, including backyard units, and cut minimum lot sizes from 5,750 to 1,800 square feet
  • San Diego, California: moved building reviews online and set a 30-day limit on approvals
  • Atlanta: put every department that handles housing into one unit under a chief housing officer to restart stalled projects

Chattanooga’s focus is the Austin model.

What it means for you

If you own a single-family home in Chattanooga, you can already apply to build an accessory dwelling unit. The 2022 ordinance set these rules, according to the city’s announcement then:

  • one unit per single-family home
  • no more than 700 square feet, in a permanent structure
  • not in the front yard setback
  • no taller than two stories, or 24 feet if the main house is one story
  • any parking lost must be replaced
  • homeowners association rules and historic district guidelines still apply

The city has not said when the permit-ready plans paid for by the grant will be available.

Our guide to building permits and zoning in Chattanooga explains how to apply, and our home prices page tracks what homes in the city are worth. Questions go to the Mayor’s Office at 423-643-7800.