Great question. None of the big sites has a reliable "ADU" filter, so here's how I'd search:
1. Use the keyword box in the filters. Try ADU, accessory dwelling, guest house, in-law suite, carriage house, garage apartment, separate entrance, and basement apartment. Agents label these units differently, so run several searches.
2. Check satellite view and photos. Look for a second structure in the backyard, then confirm it's a finished, livable unit.
3. Have an agent search the MLS. It has fields and remarks the public sites don't surface well.
Since you're buying for rental income, vet the unit before you fall for the property:
• Zoning and rental rules. These vary by city, county, and zoning district. Some places limit size, require owner occupancy, or restrict separate rentals.
•Permits. Ask for permit records and the certificate of occupancy. An unpermitted unit may not be legal to rent, and it can hurt financing and appraisals.
• Utilities and septic. Check for separate meters. If the home is on septic, check whether the system can handle the added load.
• Underwriting. Get rent comps for the ADU by itself, and underwrite it conservatively with vacancy and expenses. Ask your lender early how they treat ADU income.
What's your plan: live on-site and rent the ADU (house hack), or buy purely as an investment? That changes the search.
Ervin Kelly III, Real Estate Agent | Veribas Real Estate
I will say I've had searches running in several areas of Atlanta for the better part of 10 years and I've only had 1 house ever come up with an ADU in back.
In addition, I’ve built probably a dozen ADUs around ATL over the years. The truth is it will be like finding a needle in a haystack, because people that have/build them plan to stay.
Certainly worth a shot, but may be more feasible to search for detached garage and convert it into an ADU in the Reno. We've done those several times.