Can I Build ADU in Austin, TX? (2026)
Find out if you can build a adu in Austin, TX. Rules, permit requirements, costs, and next steps.
Whether ADUs are allowed in Austin, TX has not been confirmed — contact the local building department or see the official source before proceeding.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In Austin, TX, ADU regulations are in flux — state law and local ordinances interact to determine what is permitted. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in Austin
ADU Rules in Austin: Detached ADU max size: size varies by zoning — see official source. Attached ADU max size: size varies by zoning — see official source. Setback requirements are not confirmed — see official source. Owner-occupancy: not confirmed — see official source.
Costs & Fees
ADU permits in Austin: Contact the local building department for current fee schedule.
Next Steps
Next steps for building an ADU in Austin: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the local building department. 3. Hire a licensed contractor familiar with TX ADU requirements.
Austin Development Services Department (DSD)
Phone: (512) 978-4000 · Verified July 6, 2026 · Source
Website: https://www.austintexas.gov/development-services
Online Permits: https://abc.austintexas.gov/
Frequently Asked Questions
Can I build an ADU on my Austin property?
Yes. Austin allows secondary apartments (ADUs) on most residential lots. The unit can be up to 1,100 sqft or 0.15 FAR of lot area. No owner-occupancy requirement. With Austin's HOME Ordinance (2023), you can have up to 3 total units on most SF-zoned lots. Impervious cover limits and tree protection requirements may constrain placement.
What is the HOME Ordinance and how does it affect my property?
Austin's HOME (Home Options for Middle-Income Empowerment) Ordinance, passed in 2023 (Phase 1) and expanded in 2024 (Phase 2), allows up to 3 residential units on any single-family zoned lot in Austin. This means you can have a main house, an ADU, and a third unit — or a duplex plus a secondary apartment. Minimum lot size requirements were reduced and in some cases eliminated. This is one of the most significant zoning reforms in Austin's history.
Do I need a permit to remove a tree in Austin?
It depends on size. Trees with trunk diameters of 8 inches or more at 4.5 feet height (DBH) are 'Protected Trees' requiring an Austin permit to remove. Trees 19 inches or larger are 'Heritage Trees' — these cannot be removed except in cases of imminent public hazard (with variance approval). Austin's tree ordinance is one of the strictest in Texas and violations can result in significant fines.
Are short-term rentals (Airbnb) allowed in Austin?
Yes, with a license ($613/year). Austin has two STR types: Type 1 (owner-occupied) allows whole-unit rental without the owner present; Type 2 (non-owner-occupied) is limited to 3% of residential units per City Council district and banned in some areas. Austin collects a 9% Hotel Occupancy Tax (HOT) on STR rentals. Noise ordinance and maximum occupancy rules apply.
What are the impervious cover limits in Austin?
Impervious cover limits in Austin depend on your watershed zone and zoning district. Most SF zones allow 45% impervious cover on lots not in critical watershed areas. However, if your property is in the Barton Springs zone or other sensitive watersheds, limits drop to 25-40%. Impervious cover includes your house, garage, driveway, patio, pool, and any other hard surface. Austin Watershed Protection calculates this for each permit application.
Source: Austin Development Services Department (DSD) — Building Regulations. Last verified April 3, 2026. View source