ADU Rules in Houston, TX (2026)

Houston, TX permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In Houston, the Houston Permitting Center (HPC) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Houston.

ADU Size Limits

ADU Size Limits in Houston: Detached ADU: up to No maximum size set by Houston Development Code — deed restrictions may impose limits (max height: No height limit established by zoning — deed restrictions may apply). Attached ADU: No maximum size — deed restrictions may impose limits. Houston Development Code (Chapter 42) does not impose maximum ADU sizes — this is regulated by deed restrictions in subdivisions that have them. New construction ADUs must comply with building codes (Houston Building Code) and Development Code setbacks and lot coverage standards.

Permit Fees

ADU Permit Fees in Houston: Plan check fee: $100–$1,000. Building permit fee: Based on construction value — typically $500–$3,000. Impact fees: None. School fees: None or N/A. Total estimated permit cost: $600–$4,000 total permit fees. Houston does not charge impact fees for single-family construction. No school fees. Fee schedule: https://www.houstonpermittingcenter.org/BuildHouston/Downloads/fee.pdf

Permit Timeline

Houston ADU Permit Timeline: Houston Permitting Center (HPC) building permit: typically 2-6 weeks for residential construction. Houston uses an automated permit system for many standard construction types. Apply through the Houston Permitting Center (HPC) online permit portal. Phone: (832) 394-8803.

Setback Requirements

ADU Setback Requirements in Houston: Front setback: 10 feet. Side setback: No minimum side setback per Development Code for most lots. Rear setback: No minimum rear setback per Development Code. Houston Development Code Chapter 42 requires a 10-ft building line (setback) from public streets for residential lots less than 10,000 sqft. Larger lots have 25-ft building line. Side and rear setbacks are not mandated by Development Code — they may be required by deed restrictions. Building Code fire separation requirements apply to structures near property lines.

Parking Requirements

Parking Requirements: Houston Development Code requires a minimum of 2 off-street parking spaces per single-family dwelling unit and 1.33 spaces per multifamily unit. No additional parking specifically required for ADUs per Development Code, but deed restrictions may impose requirements.

Restrictions & Requirements

• •Deed restrictions in your subdivision may prohibit or regulate ADUs — check with Harris County Deed Records
• •Houston Development Code building line (setback) from street must be maintained
• •Building Code habitability requirements apply (ceiling height, egress, ventilation, electrical)
• •FEMA floodplain regulations apply — approximately 50% of Houston is in or near flood zones
• •Drainage requirements under City of Houston Drainage Code
• •If subdivision has HOA, deed restrictions are privately enforceable

How Many ADUs Are Allowed?

Number of ADUs Allowed in Houston: Single-family lots: No limit established by code — deed restrictions may restrict. Multifamily properties: No limit established by code — deed restrictions may restrict. Houston's lack of zoning means no code-based limit on number of units. Development Code lot size and parking minimums are the primary constraints. Deed restrictions are the practical limiting factor in most established neighborhoods.

Historic District Considerations

Frequently Asked Questions