Cost to build accessory dwelling unit — Madison, WI
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.
About this service
Building an ADU involves costs for permits, site prep, foundation, framing, plumbing, and electrical work. Prices fluctuate based on whether you choose a custom design or a pre-planned layout, as well as the complexity of connecting to existing city utilities. Exact pricing confirmed free on the call.
Frequently asked in Madison
What ADU services are available in Madison?
Who are the accessory dwelling unit companies in Madison?
What is the cost of an accessory dwelling unit in Madison?
Can I get an emergency ADU consultation in Madison?
What are the steps for accessory dwelling unit construction in Madison?
Are there affordable ADU options in Madison?
What is a detached accessory dwelling unit in Madison?
Also serving nearby: Rockford · Milwaukee · Kenosha · Elgin · Waukegan
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Madison — population 280,305; about 3,373 residents per square mile across 83.1 sq mi. ZIP codes covered include 53701, 53702, 53703, 53704, 53705, 53706, 53707, 53708.
Neighborhoods served in Madison: Isthmus, Near East Side, Westmorland, Maple Bluff, Nakoma — and every surrounding area.
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