Accessory dwelling unit cost — Boulder, CO
Last updated: September 24, 2026
What affects the price
Building an ADU involves variables that shift your total investment. The footprint size and complexity of the architectural design are primary factors. Are you planning a detached unit that requires new utility trenching, or is this a garage conversion that uses existing plumbing? Site accessibility, soil conditions, and your choice of finishes—like luxury flooring versus standard options—also play significant roles. Permitting fees vary widely depending on your local municipality and current zoning requirements. Exact pricing confirmed free on the call.
About this service
Total costs are influenced by the complexity of your site, the square footage of the unit, and the specific utility upgrades needed to support a new home. Choosing between a prefab unit and a custom build also changes your bottom line. We provide exact pricing confirmed free on the call.
Frequently asked in Boulder
Can I get a home with a mother-in-law suite in Boulder?
What are 24-hour ADU services in Boulder?
Where can I find an accessory dwelling unit contractor San Diego?
Where can I find accessory dwelling unit Massachusetts?
What are prefab ADUs in Boulder?
What is the best accessory dwelling unit for Boulder properties?
What is an accessory dwelling unit (ADU)?
Also serving nearby: Longmont · Westminster · Arvada · Thornton · Lakewood
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Boulder — population 105,898; about 3,937 residents per square mile across 26.9 sq mi. ZIP codes covered include 80301, 80302, 80303, 80304, 80305, 80306, 80307, 80308.
Neighborhoods served in Boulder: Newlands, Table Mesa, Gunbarrel, Crestview, Chautauqua — and every surrounding area.
Areas we serve
Browse by state, then city.