About Austin ADUs
The basics of accessory dwelling units and how Austin defines and regulates them.
ADU, Defined
An Accessory Dwelling Unit (ADU) is a secondary, self-contained living space located on the same lot as a primary single-family home. It has its own entrance, kitchen, bathroom, and sleeping area — separate from the main house. In Austin, ADUs are sometimes also called "granny flats," "backyard cottages," or "secondary units."
Key Things to Know
Zoning Matters
Austin's Land Development Code governs where ADUs are allowed and how large they can be relative to lot size.
Permits Are Required
An ADU is a permitted structure, not an informal add-on — it must go through plan review, permitting, and inspections.
Size Limits Apply
Austin caps ADU square footage, typically as a percentage of the lot or a flat maximum, whichever is smaller.
Parking & Setbacks
Depending on your lot and neighborhood, parking requirements and setback rules can affect what's buildable.
Popular ADU Formats in Austin
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New Detached Structure
Built from the ground up in the backyard — offers the most design freedom but generally costs the most.
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Garage Conversion
Reuses an existing structure's footprint and foundation, which can shorten timelines and reduce cost.
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Attached Addition
Built onto the existing home with a separate entrance — efficient to build but shares walls with the main house.
More ADU Resources
Keep exploring — from permitting costs to real project ideas.
Permitting Process & Costs
A step-by-step walkthrough of Austin's ADU permitting process and typical cost ranges.
Frequently Asked Questions
Quick answers to the questions Austin homeowners ask most about building an ADU.
ADU Inspiration
Real layouts and lifestyle ideas — from pool houses to multi-generational living.
ADU Rules by Zip Code
Live permit activity from the City of Austin, broken out by neighborhood.
We're also building out more in-depth resources on financing and working with the City of Austin — check back soon.
Curious What It Costs and How Long It Takes?
See a realistic breakdown of the Austin ADU permitting process and budget ranges.
Permitting Process & Costs