Centennial ADU Zoning Rules & Permit Guide

ADU Regulations in Centennial, Colorado

In Arapahoe County, Centennial regulates ADUs through local ordinance. Colorado has no statewide ADU mandate, so the city's zoning code — including lot coverage and design standards — is the governing authority.

Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Centennial as of 2026. Regulations are governed by local zoning ordinances, as Colorado has no statewide ADU mandate (HB 24-1152 addresses transit density).

Additional Local Requirements for Centennial

• Minimum lot size may apply
• Minimum 200 sq ft
• Owner occupancy may be required
• ⚠️ CO has NO statewide ADU mandate — verify with city

Frequently Asked Questions About ADUs in Centennial

Can I build an ADU in Centennial?

This Colorado city regulates ADUs through local ordinance. Confirm the minimum lot size and owner occupancy rules with the planning department.

How big can my ADU be in Centennial?

What is the maximum ADU size allowed in Centennial? ADUs in Centennial can be up to 1,000 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Centennial planning department before designing your project.

What about setbacks and other requirements in Centennial?

What are the setback requirements for an ADU in Centennial? ADUs in Centennial generally require setbacks of 5 ft rear, 5 ft side. California state law (AB 68) limits local setback requirements to 4 feet for existing structures, but always verify with local zoning.