Accessory Dwelling Unit (ADU) Regulations in Centennial

Max Size- 

• Attached/Interior: Cannot exceed 50% of the primary structure 
• Detached: 800 sq/ft

Max Height- 17’

To qualify for an ADU in Centennial, your property must meet the following conditions:

• Only one ADU is allowed per lot.
• The ADU must be accessory to a single-family home.
• ADUs are not allowed on properties with duplexes, townhomes, condos, or multifamily units.
• Short-term rentals (STRs) are regulated separately under the city’s rental guidelines.
• ADUs may be allowed in planned unit developments (PUDs) unless specifically prohibited in that district’s regulations.

Before applying for an ADU, homeowners must schedule a pre-submittal meeting with the city to ensure compliance with zoning requirements.

Centennial has specific size limitations and design standards to ensure ADUs fit within the character of residential neighborhoods:

• Maximum ADU Size:
  
  • Interior ADUs cannot exceed 50% of the total square footage of the primary residence.
  • Detached ADUs cannot exceed 800 sq/ft unless a planned unit development (PUD) zoning regulation states otherwise.
• Architectural Compatibility: The ADU must match the design, materials, and character of the primary home, including roof pitch, siding, windows, and exterior colors.
• Foundation Requirements: ADUs must be permanently affixed to an engineered foundation.
• Setbacks & Placement: ADUs must comply with zoning setbacks, ensuring proper spacing between buildings and property lines.
• Entrances: If an ADU is attached to the main home, the separate entrance should be located on the side or rear of the property to maintain neighborhood aesthetics.

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• HB 24-1152 requires cities to allow ADUs without designated parking, except in these cases:
  ✔ If no parking is currently required for the primary home, parking cannot be required for the ADU.
  ✔ If the lot does not have an existing parking space for the primary home, no additional parking is required.

• Driveways must comply with Centennial’s zoning and safety standards.

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• ADUs must be connected to the primary home’s water and sewer lines; separate utility taps are not permitted.
• All utility charges will be billed to the primary residence’s account holder.
• If an ADU requires a larger water tap size, the homeowner must pay the incremental System Development Fees based on the upgraded connection.

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• HB 24-1152 prohibits cities from requiring owner occupancy meaning ADUs can be rented out separately from the primary home.
• ADUs cannot be sold separately from the main home—they must remain part of the same lot.
• Short-term rentals (STRs) are still prohibited, except in Planned Unit Developments (PUDs) where STRs were previously allowed.

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Under HB 24-1152, all ADU approvals must be handled administratively—meaning there are:
✔ No public hearings
✔ No subjective design reviews
✔ No neighborhood approval required

Homeowners must obtain a building permit before constructing an ADU. The permit process includes:

1. Scheduling a pre-submittal meeting with the city’s Planning Department.
2. Submitting a General Permit Application with site plans, floor plans, and architectural drawings.
3. Recording a deed restriction stating that the ADU cannot be sold separately from the main home and that only one unit can be rented at a time.

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Building an ADU in Centennial requires careful planning, compliance with zoning laws, and expert execution and that’s where Kindred Tiny Homes comes in.

• We handle everything from design and permitting to construction and final approvals.
• We navigate Centennial’s ADU requirements seamlessly, ensuring your project is fully compliant and stress-free.
• We create high-quality, beautifully designed ADUs that enhance property value and maximize functionality.

If you’re considering building an ADU in Centennial, contact us today for a free consultation, we’ll walk you through your options and help bring your vision to life!

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