Also known as a Secondary Unit or In-Law Unit, or cottage. This is a Dwelling Unit as long as it provides complete independent living facilities for one or more persons including permanent provisions for living, sleeping, eating, cooking, and
sanitation, and is located on a lot with a proposed or existing single dwelling unit or multiple dwelling units.

It could be constructed either entirely within the existing built envelope, or the buildable area of an existing or proposed building in areas; or is constructed within the existing built envelope of an auxiliary structure on the same lot.

Type of ADU:

Conversion ADUs are new units that convert space in a residential building.

Attached ADUs are new units that expand a residential building.

Detached ADUs are new free-standing buildings located on a residential property.

Junior ADUs (JADU) are a new type of ADU that convert up to 500 square feet of space in a single-family structure. JADU requires owner-occupancy in either the remaining portion of the single-family home or the newly created JADU.

There are size restrictions for ADUs?  

Yes. Each jurisdiction decides on the minimum and/or maximum area as well as the maximum height of the ADU, and the minimum interior height of a space. For instance, in San Francisco and San Diego, an ADU could be at minimum 220 sqft to a max. 1,200 sqft but it cannot exceed 1/3 of the total floor area of the primary residence or unit; and it has to have a minimum 7.5 ft ceiling height.

Read more about California ADU streamlined permit process in the next article.

CityStructure report shows you the number, size and type of accessory dwelling unit you may be allowed to build on your lot.