Houston ADU Permit

What's Required in Houston

• ADUs are permitted on single-family lots but cannot exceed 900 sq ft or 50% of main house.
• Must have independent kitchen, bathroom, and a separate entrance.
• Requires a Wastewater Capacity Reservation (WCR) letter from the city.
• Must follow Chapter 42 zoning setbacks (recently relaxed in some areas to 3–5 feet).
• Must be located on a lot with an existing primary residential structure.
• Separate utility meters are optional but require individual trade permits for setup.

How Much Does an ADU Permit Cost in Houston?

Budget $1,000–$4,000 for the Houston permit itself (valuation-based), issued by the Houston Permitting Center — but treat that as the entry fee, not the total. ADUs are full dwelling units, so the permit stack usually includes building, electrical, plumbing, and mechanical trade permits, plus plan review. One local note: includes building permit, separate trade permits, and wastewater capacity reservation fees. Get an itemized fee estimate from the department before finalizing your budget; the spread between a simple conversion and a new detached build is wide.

ADU Size Limits and Zoning Rules in Houston

Before drawing plans, check the two gates that sink most ADU projects: size and zoning. Size ceilings vary by lot and ADU type (attached, detached, or conversion), so confirm your specific configuration. Other recorded conditions: must be located on a lot with an existing primary residential structure. Setbacks, height limits, and utility connections layer on top of those rules. The Houston Permitting Center can confirm what your specific lot allows — worth doing before you pay for architectural drawings rather than after.

How to Get a ADU Permit in Houston

Frequently Asked Questions