What is an ADU
ADU Education

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a second, self-contained living space on a single-family residential lot. Here’s what that means in practice — and why more Wisconsin homeowners are building them.

The Definition

A Second Home on Your Property

An ADU — Accessory Dwelling Unit — is a fully self-contained living space that exists on the same lot as a primary residence. It has its own entrance, kitchen, bathroom, and sleeping area. It functions as a complete home.

ADUs are also called: Accessory Dwelling Units, Tiny Homes, In-Law Suites, Granny Flats, Backyard Cottages, Coach Houses, Secondary Suites. The terminology varies — the concept is the same.

Under Wisconsin and local zoning law, an ADU is a permitted land use on most single-family residential lots in Dane County — subject to size limits, setbacks, and municipality-specific requirements that we navigate for you.

ADU Types

Four Types. One Specialist.

ADU interior living space
ADU exterior at dusk
Why Build One?

The Case for Adding an ADU

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Rental Income
A well-built ADU in Madison can generate $1,200–$1,800/month in rental income, creating a long-term income stream from land you already own.
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Family Proximity
Keep an aging parent or adult child close without sharing a roof. The privacy of separate structures, the convenience of being on the same lot.
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Property Value
A permitted ADU adds documented square footage and an income-producing unit to your property — one of the strongest value-adds available to homeowners.
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