Zoning Glossary

Detached ADU

A detached ADU is an accessory dwelling unit built as a separate, freestanding structure on a residential lot — physically independent from the primary dwelling, with its own foundation, walls, roof, and entrance. Common forms include backyard cottages, granny flats, and carriage houses. A detached ADU must include self-contained living facilities — kitchen, bathroom, sleeping area, and a separate exterior entrance — to qualify as a dwelling unit distinct from the primary residence.

ADU

In Practice

A detached ADU is typically built in the rear yard of a single-family lot, using the portion of the lot behind the primary dwelling. Setbacks apply to detached ADUs and may differ from the setbacks that govern the primary structure — many states have enacted laws limiting the setback distances a city may require for newly constructed detached ADUs. The detached configuration generally allows for the largest ADU footprint and, in most markets, commands the highest rental rate of the three ADU types because the unit is fully independent from the main house.

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Source: PropertyZoned Zoning Guide — ADU vs JADU: What's the Difference and Which Can You Build?. Last verified April 5, 2026.

Last updated: April 5, 2026
Detached ADU — Zoning Term Definition | PropertyZoned