Internal ADU

“Internal ADU” refers to any part of the primary home other than the basement that is converted into an ADU. For the area to be transformed into what is considered an ADU, it must have a bedroom, bathroom, and kitchen added to it.

If you have the space for this in your primary home, it could save you money in construction costs when compared to a detached or extension ADU. However, you have to be willing to give up a considerable amount of your space, which many California homeowners are not.