An Accessory Dwelling Unit (ADU) is a secondary housing unit located on a single-family lot. These units can take various forms, including:

1. Newly Constructed Stand-Alone Structure: This involves building a separate dwelling unit on your property. It could be a small cottage, studio, or tiny house.
2. Home Addition Creating a Separate Living Quarter: You can add an ADU by converting part of your existing home. For example, you might transform a garage, basement, or attic into a separate living space.
3. Conversion of Existing Space: Repurposing an existing structure, such as a garage or basement, into a separate dwelling.

ADUs go by different names, including in-law apartments, granny flats, casitas, or backyard cottages. They were more common before World War II and are considered an affordable housing option because you don’t need to purchase additional land. Land costs are often a significant factor in housing prices, especially in expensive coastal cities.

Here are some key points to consider if you’re thinking about building an ADU:

1. Check Local Regulations: Before diving into layouts and paint colors, verify with your city or county’s planning, construction, or zoning department. Make sure you’re allowed to build an ADU, understand what’s permitted, and where it can be located. State and local laws are evolving to encourage more ADU construction.
2. Homeowners Associations (HOAs): If your property falls under an HOA, review their rules as well.
3. Benefits: ADUs can provide rental income, serve as living quarters for extended family, function as a work-from-home space, or even house a home-based business.

Remember, while ADUs offer rewards, they also come with challenges.