ADU rules in Houston

Houston has no zoning, so no use permit is needed for a detached second unit. Chapter 42 expressly treats a lot with one house plus a detached second dwelling unit of not more than 1,500 sq ft as still single-family residential, which keeps it inside ordinary single-family development standards. The city promotes detached ADUs and publishes a free pre-approved detached plan set (Double House). Private deed restrictions, which the city checks and will not override, are the main thing that can prohibit one.

The same §42-1 definition classifies a lot with one building containing up to two separate dwelling units (a garage apartment over an attached garage, or an internal suite with its own kitchen) as single-family residential. With no zoning code there is no use approval to obtain; the unit must meet the Construction Code through a building permit. Deed restrictions that limit a lot to one dwelling unit would still bar it.

The 1,500 sq ft figure is a classification limit, not a hard ban: a detached second unit over 1,500 sq ft takes the lot out of the single-family category and into two-family or multi-unit treatment under Chapter 42. The Planning Department's Livable Places FAQ confirms the 2023 amendments (Ord. 2023-801, effective November 27, 2023) increased the maximum size of a second dwelling unit. Older third-party guides still cite 900 sq ft; that number appears nowhere in the current code text.

No owner-occupancy requirement for a second dwelling unit exists anywhere in the provisions that govern ADUs: the full text of Chapter 42, the Chapter 26 parking article, and the Chapter 28 short-term-rental article contain no owner-occupancy, occupied-by-owner, or homestead condition. The city's own materials describe second units as rental income for property owners with no occupancy condition. Private deed restrictions can impose their own occupancy or rental limits.

Parking for second dwelling units is size-based, set identically in §42-186 and the §26-492 use table. A unit of 1,000 sq ft or less can qualify for zero spaces on lots meeting the §42-186(a)(2) criteria. §26-471(b)(6) and (7) switch off the numeric requirements inside the mapped market-based parking area and along primary TOD streets, and a Planning Commission parking variance under Chapter 42 also counts as a variance under Chapter 26.

There is no discretionary land-use approval because Houston has no zoning; an ADU is built under a standard building permit through the Houston Permitting Center with plan review, fees, and inspections. §42-22(3) exempts construction of a detached single-family residential unit on an already-platted lot from the development plat requirement, so Planning Commission involvement arises only when subdividing land or seeking a variance. The city checks recorded deed restrictions during review and will not permit construction they prohibit.

Chapter 28 Article XXIII (adopted April 16, 2025, effective January 1, 2026) makes it unlawful to operate or advertise a short-term rental without registration; each ADU needs its own certificate, listings must display the registration number and occupancy limit, one-night minimum stays apply, and advertising special events at the rental is prohibited. Nothing in city code restricts renting an ADU on ordinary leases of 30 days or longer.