Building an ADU or garage apartment in Houston

What you can build in Houston

Houston "does not have a city-wide comprehensive zoning ordinance," according to the city's official zoning letter. The letter lists limited exceptions: land-use rules for land around the airports, and zoning rules inside Tax Increment Reinvestment Zone #1 (St. George Place). Elsewhere, the city's development rules in Chapter 42 of the Code of Ordinances control lot sizes, building lines (front setbacks along streets), driveways and parking. Private deed restrictions, where your subdivision has them, can be stricter.

Chapter 42 defines "single-family residential" as a lot with one building that contains no more than two separate dwelling units. It adds that "a free-standing building containing one dwelling unit and a detached second dwelling unit of not more than 1500 square feet shall also be considered single-family residential."

In practice that means two common options:

• a detached second dwelling unit (SDU), such as a garage apartment or backyard cottage, of up to 1,500 sq ft;
• two units in one building, which the city's FAQ describes as the code allowing "duplexes on a single-family lot."

The city's Livable Places User Guide says an SDU, also known as an accessory dwelling unit or ADU, "is typically located above a garage or within a separate structure from the first unit." Texas has no statewide ADU law, so these city rules and your deed restrictions decide what you can build. See our Texas ADU guide and what is an ADU. [1][2][4][5][6][7]

Livable Places: the 2023 changes

City Council approved the Livable Places housing amendments to Chapters 42 and 26 on September 27, 2023. They took effect on November 27, 2023.

For second dwelling units, the change raised the maximum size "from 900 to 1,500 square feet" and based parking on the unit's size instead of its number of bedrooms. The city says the larger size applies "where deed restrictions do not prohibit their construction."

The rules apply to new development and redevelopment inside the city limits, not in Houston's extraterritorial jurisdiction (ETJ). They did not apply to projects that had already started permitting before the change. Read more on the city's Livable Places page. [4][7][8]

Deed restrictions come first

Many Houston neighborhoods have deed restrictions, and they can ban a second unit even though city rules allow one. The city's Livable Places FAQ says: "The City has no authority to override or supersede active, private deed restrictions." Its example: the code allows duplexes on a single-family lot, but the city "does not allow construction of a duplex if deed restrictions prohibit more than one dwelling unit on a lot."

The city also enforces some deed restrictions itself. Under Chapter 212 of the Texas Local Government Code and Chapter 10 of the city code, the Legal Department can sue over restrictions that affect land use, setbacks, lot size, or "the size, type and number of structures that may be built on the lot." For questions, call the Deed Restriction Hotline at 832-393-6333. City attorneys say they cannot give individual legal advice, so read your own restrictions, or have a private attorney review them, before you design anything.

Some blocks also have a Special Minimum Lot Size or Special Minimum Building Line set through Chapter 42. Check your address on the city's Special Minimum Lot Size and Building Line page. [4][9][10]

Parking

Parking for a second dwelling unit depends on its size. Under Section 42-186, if the main home meets its own parking requirement:

• a second unit of not more than 1,000 gross square feet needs no additional off-street space;
• a second unit of more than 1,000 but no more than 1,500 sq ft needs one additional space.

The main home itself generally needs two off-street spaces, or one space if the unit is no more than 1,500 sq ft. The city's user guide adds that an SDU needs an extra space if the first unit does not meet its parking requirement.

On lots narrower than 33 feet, the user guide says you get one 12-foot driveway per street frontage, with no extra driveway for the SDU. Where possible, an SDU "should take vehicular access from an alley." [3][6]

Setbacks, lot size and splitting a lot

Houston's Chapter 42 building lines are measured from streets. On a lot restricted to single-family use along a local street, the standard building line is 20 feet in front and 10 feet along a side or back that faces a local street, with a 20-foot line for a garage or carport facing the street. Optional performance standards and plat notes can allow smaller lines. Deed restrictions may set their own setbacks.

New lots inside the city must generally be at least 3,500 sq ft where there is wastewater service. They can be smaller (down to an average of 1,400 sq ft in some layouts) if the plat meets Chapter 42 performance standards, such as shared driveways. The city says owners can still subdivide lots under the Livable Places rules. New lots under 33 feet wide that take access only from the street must share a driveway under the Livable Places rules.

New construction usually needs a development plat. Chapter 42 exempts a detached single-family unit built in compliance with a recorded subdivision plat; the Planning Department can tell you whether your project needs one. [4][9][11][12][13]

Permits, fees and timeline

A new garage apartment or backyard unit, or a conversion of an existing building, is permitted through the Houston Permitting Center as a New Residential Construction Permit. That permit covers "new homes or residential accessory structures, remodel or conversion of existing buildings or additions."

You apply online through iPermits, pay the plan review fee, and then get an email invitation to upload plans. Depending on scope, review can involve structural, planning, utilities, stormwater, traffic, trade, forestry, fire and flood plain groups. The posted processing time is 15 business days and the permit is valid for 6 months.

Fees follow the City of Houston fee schedule, plus a $33.56 admin fee. The Permitting Center has a fee calculator. A legal form survey must be given to the inspector at the first structural inspection for all new construction and additions. See our ADU permit process guide and ADU cost guide. [14]

Garage conversions

The same New Residential Construction Permit covers the "remodel or conversion of existing buildings," so turning a detached garage into a living unit goes through residential plan review.

If you convert a garage, check parking. Under Section 42-186 the main home must still meet its own off-street parking requirement for a second unit of up to 1,000 sq ft to need no added space. Our garage conversion guide covers the general steps. [3][14]

Free ADU plans from the city

The Planning and Development Department offers a free set of plans for "Double House," a detached secondary unit from its ADU | HOU Design Competition. The plans "have gone through preliminary review by Houston Public Works but may require additional steps for permitting and construction."

The city says you still need to check that your deed restrictions allow an ADU and rent, submit plans, get permits, develop a site plan, pay fees and schedule inspections. You may need an architect, engineer or developer to adapt the design to your site. Download the Double House design set. See also our prefab ADU guide. [15]

Renting it out and short-term rentals

Houston now registers short-term rentals. City Council approved the ordinance on April 16, 2025, and the city began taking registrations August 1, 2025. A short-term rental is a dwelling unit, or part of one, rented or offered "for a period of less than 30 consecutive days." The annual registration fee is $275 per rental property.

You need a city certificate of registration and must give its number to listing platforms. Starting January 1, 2027, the city will begin asking platforms to remove listings without one. Register through the city's Short-Term Rentals page, or call 832-394-8802.

Your deed restrictions may also limit renting; the city's ADU plan release tells owners to verify whether deed restrictions allow "the construction and rental of ADUs." [15][16][17]

Permit steps in Houston

1. Read your deed restrictions

   Check whether your subdivision's deed restrictions allow a second unit and rentals. The city can't override them. Questions about city enforcement go to the Deed Restriction Hotline. [4][9][15]

2. Check Chapter 42 limits for your lot

   Keep a detached unit at or under 1,500 sq ft, plan parking by unit size, and check building lines and any Special Minimum Lot Size or Building Line on your block. [2][3][10]

3. Get plans drawn

   Prepare a complete plan set and the Residential Prerequisite Checklist (CE-1301). The city's free Double House plans are one starting point. [14][15]

4. Apply for a New Residential Construction Permit

   Create an iPermits account, complete the building permit application and declaration, pay the plan review fee, and upload plans when invited. Posted processing time is 15 business days. [14]

5. Build and pass inspections

   Keep the permit and plans on site. Give the inspector a legal form survey at the first structural inspection. Schedule inspections online or by phone (IVR) at 713-222-9922. [14]

6. Register if you'll rent short term

   Stays under 30 consecutive days need a city short-term rental certificate of registration. [16]

Pre-approved and sample plans

• ADU | HOU "Double House" design set

  Free plans for a detached secondary unit that had preliminary review by Houston Public Works; site-specific work and permits still needed. [15]

Who to call

• Houston Permitting Center

  Building permits, plan review and inspections

  832-394-9000

  1002 Washington Avenue, Houston, TX 77002

  [14]

• Houston Public Works, Structural Inspections

  Structural inspections and reinspections

  832-394-8840

  [14]

• Planning and Development Department (Livable Places)

  Chapter 42 second dwelling unit, lot and parking rules

  832-393-6600

  [7]

• Legal Department, Deed Restriction Enforcement

  Questions about deed restrictions the city enforces

  832-393-6333

  [9]

• Short-Term Rental registration (Administration & Regulatory Affairs)

  Short-term rental certificates of registration

  832-394-8802

  [16]

Questions people ask