Accessory dwelling unit permit cost — Billings, MT
Last updated: September 24, 2026
What affects the price
Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.
Frequently asked in Billings
What does 'accessory dwelling unit' mean in Billings?
In Billings, an accessory dwelling unit (ADU) refers to a second, independent living space on a property that already has a primary residence. It must have its own kitchen, bathroom, and sleeping area. ADUs can be detached structures like backyard cottages or attached to the main home. They are regulated by Billings' zoning ordinances to ensure proper integration into the neighborhood. We can help you understand these rules.
Are there affordable ADU options in Billings?
What are the options for a prefab ADU in Billings?
Can I build a modular ADU in Billings?
Yes, modular ADUs are a viable option for construction in Billings. Similar to prefab units, modular ADUs are constructed in sections in a factory setting and then assembled on your lot. This method can streamline the building process. It's essential that the modular unit meets all state building codes and local Billings zoning requirements. We work with providers of modular ADU solutions.
Who are the ADU builders in Billings?
What is the process for ADU construction in Billings?
How much does an ADU cost in Billings?
Also serving nearby: Salt Lake City · West Valley City · Sandy · West Jordan · Fort Collins
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Billings — population 120,864; about 2,652 residents per square mile across 45.6 sq mi. ZIP codes covered include 59101, 59102, 59103, 59104, 59105, 59106, 59107, 59108.
Neighborhoods served in Billings: West End, Heights, Downtown Billings, North Park, South Park — and every surrounding area.
Areas we serve
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