As of October 2026, Austin's HOME amendments allow up to three housing units on lots zoned SF-1, SF-2 and SF-3, a change that took effect for applications on February 5, 2024. The city eliminated the old "primary" and "secondary" unit distinction. Coverage, setbacks, floor-area limits and private deed restrictions still shape what fits.
What did HOME Phase 1 change?
- Up to three units, including tiny homes, on SF-1, SF-2 and SF-3 lots.
- Guest houses, employee housing and accessory apartments are no longer separate accessory categories; they are units in a two-unit or three-unit use.
- Each unit in a two-unit or three-unit use needs its own address.
- Limits on the number of unrelated adults per unit were removed.
- The city lists 40% building coverage for duplex, two-unit and three-unit uses.
Is there a size cap on the second unit?
Not a single fixed number. Before HOME, local guides describe a cap of 1,100 sq ft or 15% of lot area. Now the coverage and impervious cover limits, setbacks and, inside the McMansion boundary, floor-area rules set the size. A tiny home is defined as 400 sq ft or less, not counting a loft.
Is owner occupancy required?
Published guides to the post-HOME rules report that Austin does not require owner occupancy for these units. Confirm with the city for your specific use, since rules can change.
Is parking required?
Austin removed minimum parking requirements in 2023, so city code does not require a space for the new unit.
What was HOME Phase 2?
Adopted May 16, 2024, it created a small-lot single-family use for lots of at least 1,800 sq ft and under 5,750 sq ft, one unit per lot. It mostly affects subdivision and new small homes, not ADUs on existing lots.
It depends: what still limits an Austin ADU?
- McMansion boundary. All enclosed space, including garages and lofts, counts toward floor area.
- Preservation bonus. Keeping part of an existing house can exempt that part from floor-area totals if code conditions are met.
- Trees, floodplain and drainage. Separate city rules apply.
- Deed restrictions. City zoning does not cancel private restrictions. See HOAs and deed restrictions.
- Short-term rental. Austin licenses short-term rentals separately; check those rules before planning nightly stays.
Sources, as of October 2026:
- City of Austin Development Services, "HOME Amendments" page, for Phase 1 and Phase 2 provisions and dates.
- Neuhaus Realty Group, ADU guide (August 2026), and JDJ Consulting, "Austin ADU Rules in 2026," for owner-occupancy, parking and the pre-HOME size cap as reported.