ADU Guide · Verified 2026
Building an ADU in Texas
Texas has no statewide ADU law at all. Whether you can build one, and under what size, setback, or parking rules, depends entirely on your specific city or county. Austin is the most permissive major city after its 2023 HOME Ordinance; Houston has no zoning ordinance citywide but still enforces its own building and platting rules; Dallas and San Antonio are more restrictive. A bill that would have created a statewide framework, SB 673, died in the 2025 legislative session.
Quick Facts
Statewide floors set by No statewide ADU statute; each city sets its own ordinance. Your city may be more generous but cannot go below them.
The Three Types of ADU
No state floor to rely on
Unlike California, Washington, or even Arizona's HB 2720 for large cities, Texas has never passed a statewide ADU law of any kind. Every rule, from whether an ADU is allowed at all to its maximum size, comes from the specific city or county where the property sits. There is no default answer for "can I build an ADU in Texas", the question only makes sense once you name the city.
A bill that tried and failed
SB 673 (2025) would have prohibited local governments from banning ADU construction, leasing, or conversion on single-family and duplex-zoned lots, with lots under 10,000 square feet allowed to host two units. It was engrossed but died before passage. A follow-up, SB 1412, has been filed by State Senator Bryan Hughes for a future session but has not become law as of this writing.
Austin is the model for permissive Texas cities
Austin's 2023 HOME (Home Options for Middle-income Empowerment) Ordinance removed the off-street parking requirement for ADUs and raised the allowed size to up to 1,100 square feet on qualifying lots, among the most permissive rules of any major Texas city.
Houston's lack of zoning does not mean no rules
Houston is famous for having no traditional zoning ordinance, but that does not mean ADUs are unregulated there. The city still enforces building permits, platting requirements, and minimum lot size rules through its development code, and Houston is generally considered relatively permissive for ADU construction compared to Dallas or San Antonio.
Dallas and San Antonio require more navigation
Both cities require ADU-specific zoning review in most residential districts, with stricter size, setback, and sometimes owner-occupancy conditions than Austin or Houston. Confirming the specific zoning district before investing in design work matters more in these cities than in Austin.
HOAs remain a real barrier
No Texas state law preempts homeowners association covenants the way California's Civil Code § 4751 does. If a subdivision's recorded HOA documents prohibit accessory structures or secondary dwelling units, that restriction holds even where the city's zoning would otherwise allow an ADU.
What people get wrong
The most common mistake is assuming a rule confirmed in Austin applies statewide, or even in the next Texas city over. With no state floor and four of the largest US cities taking four different approaches, the local planning department is the only reliable source, not a general "Texas ADU law."
From Idea to Move-In: The Timeline
Who Administers It
Counties With Their Own Rules
These Texas counties have verified, county-specific ADU rules that add to the state baseline:
Building It Yourself? Here's What You'll Need
Planning an ADU? Tools homeowners use in the design and layout phase:
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Check Your Local Rules
Your city may allow more than the state floor
State law sets the minimum; many Texas cities and counties are more generous. Browse the full directory of 254 counties and every city in Texas for local rules, fees, and building department contact details.
Browse the full Texas directory →Not sure if your project needs a building permit, a zoning approval, or both? See our guide to building permits vs. zoning approval.
Official Sources
ADU law changes frequently and local ordinances add detail. This guide is general information, not legal advice, always confirm with your local building department. Reviewed by the StateDataIndex Editorial Team · Updated September 2026.