ADU Requirements

What is an ADU?

An ADU / DADU (or accessory dwelling unit), can also be known as a backyard cottage, accessory apartment, carriage house, mother-in-law suite, or granny flat. Whatever term you use, this type of smaller home is usually an additional living space located on the same piece of property as an existing home. While it can also be a new home on an existing plot of land by itself, in order to be classified as an ADU, it must be self-sufficient – the living space must include areas for living, sleeping, eating, cooking, and sanitation.

Many counties and cities have their own “codes” as to what is truly an ADU. Since some municipalities might require that the ADU and existing home match, our in-house design team can modify any of our ADU home plans for you. You will want to verify all laws and codes yourself, but we have put together some ADU requirements for specific municipalities.

Tacoma/Pierce County ADU Requirements:

Kitsap County ADU Requirements:

Seattle ADU Requirements:

Snohomish County ADU Requirements: