Cost of accessory dwelling unit — 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
Building an ADU involves several variables that shift your final total, such as the size of the unit, whether you choose a detached structure or a garage conversion, and the complexity of your site’s plumbing and electrical needs. We help you navigate these choices to keep your project on track. Exact pricing confirmed free on the call.
Frequently asked in Boulder
What is an ADU unit and how does it work in Boulder?
What is the cost to build an accessory dwelling unit in Boulder?
What are the financing options for an accessory dwelling unit in Boulder?
Where can I find an accessory dwelling unit contractor in Boulder?
Are prefab ADUs a good option for Boulder?
What does accessory dwelling unit mean in terms of building codes?
When we talk about accessory dwelling unit in terms of building codes, it means these units must meet specific safety and construction standards set by the local jurisdiction. This includes requirements for structural integrity, electrical, plumbing, and fire safety. Boulder has its own set of codes. The pros we work with are well-versed in these regulations.
What are the available ADU services in Boulder?
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: Gunbarrel, Newlands, Whittier, Table Mesa, Mapleton Hill — and every surrounding area.
Areas we serve
Browse by state, then city.