Building an ADU in Austin: zoning, permits, rental rules

Short answer

An Additional Dwelling Unit is a second home on the same lot as a single-family house: habitable space, a full bathroom, and a sink or dishwasher outside the bathroom. In Austin you can build one if the property is zoned SF-1, SF-2, or SF-3 (check Property Profile) and the lot is at least 5,750 square feet. Recent code changes removed the minimum distance between units, and the HOME amendments now allow multiple units on certain lots. Every new unit needs its own address from Address Management before you apply. Permits go through the Austin Build + Connect (AB+C) portal, and the applicant named on the permit needs their own AB+C account to pay fees and manage the file. Planning to rent it short-term? A unit built after October 1, 2015 can be a short-term rental for no more than 30 days per calendar year, and you will need the Certificate of Occupancy and an STR license. Watch for deed restrictions: they can block an ADU even when zoning allows it, and checking them is on you.

Who this is for

Austin homeowners scoping a backyard cottage, garage apartment, or in-law unit, and buyers checking whether a property can take one.

The steps, in order

1. Confirm the zoning is SF-1, SF-2, or SF-3 on the city's Property Profile tool.
2. Measure the lot: 5,750 square feet minimum. Check deed restrictions and restrictive covenants on the property before spending on plans.
3. Under the HOME amendments, look at whether the lot qualifies for two or three units instead of one.
4. Get a unique address or building number for the unit from Address Management Services before submitting the permit.
5. Create an AB+C portal account in the applicant's name; that account pays fees and manages the application.
6. Submit the residential building permit application in AB+C, then pass final inspections to get the Certificate of Occupancy.
7. Want STR income? If the unit was built after October 1, 2015, short-term rental use is capped at 30 days per calendar year and needs a license.

Have this ready

• The property's zoning district (SF-1, SF-2, or SF-3) from Property Profile
• Lot size of at least 5,750 sqft
• A deed-restriction check on the property
• An AB+C portal account in the applicant's name
• A new address for the unit from Address Management

Common mistakes to avoid

• Assuming zoning alone settles it. Deed restrictions and restrictive covenants can block an ADU, and the city puts that check on the applicant.
• Skipping the new address. Each unit requires a unique address before the permit application goes in.
• Planning year-round Airbnb income on a newer unit. Post-October 2015 ADUs cap short-term rental use at 30 days per calendar year.
• Using the wrong AB+C account. The applicant listed on the permit must own the account that pays and manages the file.
• Forgetting the Certificate of Occupancy. It is issued only after final inspections, and an STR license application needs it.

Common questions

What lots can have an ADU in Austin?

Properties zoned SF-1, SF-2, or SF-3 with at least 5,750 square feet of lot area, subject to deed restrictions. The HOME amendments allow multiple units on certain zoned lots.

Do the two units need to be a minimum distance apart?

Zoning no longer sets a minimum distance between units, but technical codes still apply, including fire separation under IRC R302.1(1).

Can I Airbnb an ADU?

Only up to 30 days per calendar year if the unit was built after October 1, 2015, and only with a short-term rental license plus the Certificate of Occupancy.

Where do I apply for the permit?

In the Austin Build + Connect (AB+C) portal. The named applicant needs their own AB+C account to pay fees and manage the application.

Official source

• Austin Development Services: Additional Dwelling Units

Checked August 26, 2026. Recheck the official page monthly and when the official page changes.

Related

• File a Travis County homestead exemption
• Austin residential parking permits (RPP)