If you are wondering how big you can build your ADU, you are not alone. Size requirements are a big aspect of determining how your ADU will be designed, planned, and budgeted. Determining what size will work best for you early on can make a world of difference in speeding up the designing and planning process. That is why we put together this quick guide to ADU size requirements.
Basic ADU Requirements
To start, every ADU, regardless of what type it is, has to be at least 150 square feet. It needs to contain a kitchen with a sink and stove that is at least 50 square feet. It also needs a bathroom with a bathing area that is at least 30 square feet. Don’t forget about the mandatory living area as well.
If you plan to build an ADU this small, make sure you do the best you can to make use of all the space possible. Here are some ADU furniture and appliance options that can help make the most out of such a small space.
If you want an ADU smaller than this, you can try to apply for a discretionary permit. You are going to need a very good case though because these are very rarely handed out.
General Max Sizes
Every city and region will have its own set of rules when it comes to the maximum size that you can build your ADU. However, everywhere you go will allow an ADU to be up to 800 square feet. On average though, most detached ADUs are allowed to be up to 1,200 square feet. Attached ADUs can be up to 50% of the primary structure’s square footage and conversions don’t usually have limitations since the structure already exists.
Figuring Out Your Size Requirements
To find the exact size requirements that pertain to you, you will need to get in touch with your local planning board. They will be able to identify what zone you fall in and the corresponding laws that go with that zone. You can also work with a local ADU professional. They will be able to do the same things for you.